Phase 2 seam: expose pure helpers for testing (no logic changes)

Every change here is either dropping `private` (still invisible
outside the module, @testable import just needs internal-or-wider)
or converting a self-independent instance method to `static func`
(ChatViewModel.inferProvider/calculateCost/detectGoodbyePhrase --
none of the three ever touched `self`, and constructing a real
ChatViewModel triggers a real network call in init, so static-ifying
them sidesteps that entirely rather than fighting it). Call sites
updated to `Self.foo(...)` where the static conversion required it.

Touches: GitSyncService's URL/secret-scanning helpers,
EmbeddingService's embedding (de)serialization, ContextSelectionService's
importance scoring, and the request-building/response-parsing helpers
on all four providers (OpenRouter, Ollama, OpenAI, Anthropic) -- the
core AI request/response layer, previously 100% untested.

Verified: full existing test suite (27 tests) still green, no
regressions. Tests for these functions land in the next commit.
Phase 2 of the test-suite rollout plan (peaceful-baking-kurzweil).

oAI/Providers/AnthropicProvider.swift

@@ -571,7 +571,7 @@ class AnthropicProvider: AIProvider {
 
     // MARK: - Request Building
 
-    private func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> (URLRequest, Data) {
+    func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> (URLRequest, Data) {
         let url = messagesURL
 
         // Separate system message
@@ -685,7 +685,7 @@ class AnthropicProvider: AIProvider {
         return (urlRequest, bodyData)
     }
 
-    private func parseResponse(data: Data) throws -> ChatResponse {
+    func parseResponse(data: Data) throws -> ChatResponse {
         guard let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
             throw ProviderError.invalidResponse
         }
@@ -741,7 +741,7 @@ class AnthropicProvider: AIProvider {
         )
     }
 
-    private func convertParametersToDict(_ params: Tool.Function.Parameters) -> [String: Any] {
+    func convertParametersToDict(_ params: Tool.Function.Parameters) -> [String: Any] {
         var props: [String: Any] = [:]
         for (key, prop) in params.properties {
             var propDict: [String: Any] = [

oAI/Providers/OllamaProvider.swift

@@ -275,7 +275,7 @@ class OllamaProvider: AIProvider {
 
     // MARK: - Helpers
 
-    private func buildRequestBody(from request: ChatRequest, stream: Bool) -> [String: Any] {
+    func buildRequestBody(from request: ChatRequest, stream: Bool) -> [String: Any] {
         var messages: [[String: Any]] = []
 
         // Add system prompt as a system message
@@ -301,7 +301,7 @@ class OllamaProvider: AIProvider {
         return body
     }
 
-    private func parseOllamaResponse(_ json: [String: Any], model: String) -> ChatResponse {
+    func parseOllamaResponse(_ json: [String: Any], model: String) -> ChatResponse {
         let message = json["message"] as? [String: Any]
         let content = message?["content"] as? String ?? ""
         let promptTokens = json["prompt_eval_count"] as? Int ?? 0

oAI/Providers/OpenAIProvider.swift

@@ -117,7 +117,7 @@ class OpenAIProvider: AIProvider {
         }
     }
 
-    private func fallbackModels() -> [ModelInfo] {
+    func fallbackModels() -> [ModelInfo] {
         Self.knownModels.map { id, info in
             ModelInfo(
                 id: id,
@@ -283,7 +283,7 @@ class OpenAIProvider: AIProvider {
 
     // MARK: - Helpers
 
-    private func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> URLRequest {
+    func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> URLRequest {
         let url = URL(string: "\(baseURL)/chat/completions")!
 
         var apiMessages: [[String: Any]] = []
@@ -358,7 +358,7 @@ class OpenAIProvider: AIProvider {
         return urlRequest
     }
 
-    private func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) -> ChatResponse {
+    func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) -> ChatResponse {
         guard let choice = apiResponse.choices.first else {
             return ChatResponse(id: apiResponse.id, model: apiResponse.model, content: "", role: "assistant", finishReason: nil, usage: nil, created: Date())
         }

oAI/Providers/OpenRouterProvider.swift

@@ -416,7 +416,7 @@ class OpenRouterProvider: AIProvider {
     
     // MARK: - Helper Methods
     
-    private func buildAPIRequest(from request: ChatRequest) throws -> OpenRouterChatRequest {
+    func buildAPIRequest(from request: ChatRequest) throws -> OpenRouterChatRequest {
         let apiMessages = request.messages.map { message -> OpenRouterChatRequest.APIMessage in
 
             let hasAttachments = message.attachments?.contains(where: { $0.data != nil }) ?? false
@@ -500,7 +500,7 @@ class OpenRouterProvider: AIProvider {
         )
     }
     
-    private func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) throws -> ChatResponse {
+    func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) throws -> ChatResponse {
         guard let choice = apiResponse.choices.first else {
             throw ProviderError.invalidResponse
         }
@@ -540,7 +540,7 @@ class OpenRouterProvider: AIProvider {
         )
     }
 
-    private func convertToStreamChunk(_ apiChunk: OpenRouterStreamChunk) throws -> StreamChunk {
+    func convertToStreamChunk(_ apiChunk: OpenRouterStreamChunk) throws -> StreamChunk {
         guard let choice = apiChunk.choices.first else {
             throw ProviderError.invalidResponse
         }
@@ -579,7 +579,7 @@ class OpenRouterProvider: AIProvider {
     }
 
     /// Decode base64 data URL images from API response
-    private func decodeImageOutputs(_ outputs: [OpenRouterChatResponse.ImageOutput]) -> [Data]? {
+    func decodeImageOutputs(_ outputs: [OpenRouterChatResponse.ImageOutput]) -> [Data]? {
         let decoded = outputs.compactMap { output -> Data? in
             let url = output.imageUrl.url
             // Strip "data:image/...;base64," prefix

oAI/Services/ContextSelectionService.swift

@@ -214,7 +214,7 @@ final class ContextSelectionService {
     // MARK: - Importance Scoring
 
     /// Calculate importance score (0.0 - 1.0) for a message
-    private func getImportanceScore(_ message: Message) -> Double {
+    func getImportanceScore(_ message: Message) -> Double {
         var score = 0.0
 
         // Factor 1: Cost (expensive calls are important)
@@ -248,7 +248,7 @@ final class ContextSelectionService {
     // MARK: - Token Estimation
 
     /// Estimate token count for messages (rough approximation)
-    private func estimateTokens(_ messages: [Message]) -> Int {
+    func estimateTokens(_ messages: [Message]) -> Int {
         var total = 0
         for message in messages {
             if let tokens = message.tokens {

oAI/Services/EmbeddingService.swift

@@ -348,7 +348,7 @@ final class EmbeddingService {
     // MARK: - Serialization
 
     /// Serialize embedding to binary data (4 bytes per float, little-endian)
-    private func serializeEmbedding(_ embedding: [Float]) -> Data {
+    func serializeEmbedding(_ embedding: [Float]) -> Data {
         var data = Data(capacity: embedding.count * 4)
         for value in embedding {
             var littleEndian = value.bitPattern.littleEndian
@@ -360,7 +360,7 @@ final class EmbeddingService {
     }
 
     /// Deserialize embedding from binary data
-    private func deserializeEmbedding(_ data: Data) -> [Float] {
+    func deserializeEmbedding(_ data: Data) -> [Float] {
         var embedding: [Float] = []
         embedding.reserveCapacity(data.count / 4)
 

oAI/Services/GitSyncService.swift

@@ -507,7 +507,7 @@ class GitSyncService {
         }
     }
 
-    private func detectSecretsInText(_ text: String) -> [String] {
+    func detectSecretsInText(_ text: String) -> [String] {
         let patterns: [(name: String, pattern: String)] = [
             ("OpenAI Key", "sk-[a-zA-Z0-9]{32,}"),
             ("Anthropic Key", "sk-ant-[a-zA-Z0-9_-]+"),
@@ -610,7 +610,7 @@ class GitSyncService {
         }
     }
 
-    private func convertToSSH(_ url: String) -> String {
+    func convertToSSH(_ url: String) -> String {
         // If already SSH format, return as-is
         if url.hasPrefix("git@") {
             return url
@@ -642,7 +642,7 @@ class GitSyncService {
         return url
     }
 
-    private func injectCredentials(_ url: String, username: String, password: String) -> String {
+    func injectCredentials(_ url: String, username: String, password: String) -> String {
         // Convert https://github.com/user/repo.git
         // To: https://username:password@github.com/user/repo.git
 
@@ -697,7 +697,7 @@ class GitSyncService {
         }
     }
 
-    private func sanitizeFilename(_ name: String) -> String {
+    func sanitizeFilename(_ name: String) -> String {
         // Remove invalid filename characters
         let invalid = CharacterSet(charactersIn: "/\\:*?\"<>|")
         return name.components(separatedBy: invalid).joined(separator: "-")

oAI/ViewModels/ChatViewModel.swift

@@ -413,15 +413,15 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// Update the selected model and keep currentProvider + settings in sync.
     /// Call this whenever the user picks a model in the model selector.
     func selectModel(_ model: ModelInfo) {
-        let newProvider = inferProvider(from: model.id) ?? currentProvider
+        let newProvider = Self.inferProvider(from: model.id) ?? currentProvider
         selectedModel = model
         currentProvider = newProvider
         MCPService.shared.resetBashSessionApproval()
     }
 
-    func inferProviderPublic(from modelId: String) -> Settings.Provider? { inferProvider(from: modelId) }
+    func inferProviderPublic(from modelId: String) -> Settings.Provider? { Self.inferProvider(from: modelId) }
 
-    private func inferProvider(from modelId: String) -> Settings.Provider? {
+    static func inferProvider(from modelId: String) -> Settings.Provider? {
         // OpenRouter models always contain a "/" (e.g. "anthropic/claude-3-5-sonnet")
         if modelId.contains("/") { return .openrouter }
         // Anthropic direct (e.g. "claude-sonnet-4-5-20250929")
@@ -437,7 +437,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// Shows a system message only on failure or on a successful switch.
     @MainActor
     private func switchToConversationModel(_ modelId: String) async {
-        guard let targetProvider = inferProvider(from: modelId) else {
+        guard let targetProvider = Self.inferProvider(from: modelId) else {
             showSystemMessage("⚠️ Could not determine provider for model '\(modelId)' — keeping current model")
             return
         }
@@ -942,7 +942,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                             messages[index].tokens = usage.completionTokens
                             if let model = selectedModel {
                                 let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                                let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                                let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                                 messages[index].cost = cost
                                 sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                             }
@@ -1006,7 +1006,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                             messages[index].tokens = usage.completionTokens
                             if let model = selectedModel {
                                 let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                                let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                                let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                                 messages[index].cost = cost
                                 sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                             }
@@ -1306,7 +1306,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                         sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                     }
                 }
-                _ = detectGoodbyePhrase(in: "")
+                _ = Self.detectGoodbyePhrase(in: "")
             } catch {
                 if let index = messages.firstIndex(where: { $0.id == messageId }) {
                     messages[index].content = "❌ Image generation failed: \(error.localizedDescription)"
@@ -1582,7 +1582,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                     // Nothing worth showing yet — still record usage/cost for this turn.
                     if let usage = totalUsage, let model = selectedModel {
                         let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                        let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                        let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                         sessionStats.addMessage(
                             inputTokens: usage.promptTokens,
                             outputTokens: usage.completionTokens,
@@ -1607,7 +1607,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                     // Calculate cost
                     if let usage = totalUsage, let model = selectedModel {
                         let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                        let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                        let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                         if let index = messages.lastIndex(where: { $0.id == assistantMessage.id }) {
                             messages[index].cost = cost
                         }
@@ -2038,7 +2038,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     }
 
     /// Detect goodbye phrases in user message
-    func detectGoodbyePhrase(in text: String) -> Bool {
+    static func detectGoodbyePhrase(in text: String) -> Bool {
         let lowercased = text.lowercased()
         let goodbyePhrases = [
             "bye", "goodbye", "bye bye", "good bye",
@@ -2078,7 +2078,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
         updateConversationTracking()
 
         // Check for goodbye phrase
-        if detectGoodbyePhrase(in: text) {
+        if Self.detectGoodbyePhrase(in: text) {
             Log.ui.info("Goodbye phrase detected - triggering auto-save")
             // Wait a bit to see if user continues
             try? await Task.sleep(for: .seconds(30))
@@ -2259,7 +2259,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// pricing when present: cache writes cost 1.25x the base input rate, cache
     /// reads cost 0.1x. `usage.promptTokens` is already the uncached remainder —
     /// it does not need cache tokens subtracted from it.
-    private func calculateCost(usage: ChatResponse.Usage, pricing: ModelInfo.Pricing) -> Double {
+    static func calculateCost(usage: ChatResponse.Usage, pricing: ModelInfo.Pricing) -> Double {
         let inputCost = Double(usage.promptTokens) * pricing.prompt / 1_000_000
         let cacheReadCost = Double(usage.cacheReadInputTokens ?? 0) * pricing.prompt * 0.1 / 1_000_000
         let cacheWriteCost = Double(usage.cacheCreationInputTokens ?? 0) * pricing.prompt * 1.25 / 1_000_000