Add personal data tools, 2nd Brain trust toggle, and research agents

Personal Data Tools: native Calendar, Reminders, Contacts (hidden pending
Apple TCC fix in beta), and Location & Maps access via EventKit, Contacts
framework, and MapKit. Write actions (create event/reminder, complete
reminder) gate through an approval sheet. Four hardened-runtime entitlements
added to oAI.entitlements; Info.plist usage strings added for all services.
Personal Data section shows a β badge while Contacts is hidden.

2nd Brain always-trust: inline toggle on the Agent Skills row for the skill
named "2nd Brain" skips the bash approval dialog when the command contains
.brain_helper.py, gated by three runtime checks in MCPService.

Research agents: spawn_research_agents tool runs up to 5 concurrent read-only
sub-agents (read_file, list_directory, search_files, web_search — no write,
no bash, no nesting). Bounded by maxConcurrentAgents setting (default 3) and
a hard ceiling of 8 tasks. Added items field to Tool.Function.Parameters.Property
for JSON Schema array support; wired into AnthropicProvider.convertParametersToDict.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

oAI/oAI-InfoPlist.xcstrings

@@ -36,6 +36,54 @@
           }
         }
       }
+    },
+    "NSCalendarsFullAccessUsageDescription" : {
+      "comment" : "Privacy - Calendars Full Access Usage Description",
+      "extractionState" : "extracted_with_value",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "new",
+            "value" : "oAI can read and create calendar events when you ask it to, if you enable Calendar access in Settings."
+          }
+        }
+      }
+    },
+    "NSContactsUsageDescription" : {
+      "comment" : "Privacy - Contacts Usage Description",
+      "extractionState" : "extracted_with_value",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "new",
+            "value" : "oAI can search your contacts when you ask it to, if you enable Contacts access in Settings."
+          }
+        }
+      }
+    },
+    "NSLocationWhenInUseUsageDescription" : {
+      "comment" : "Privacy - Location When In Use Usage Description",
+      "extractionState" : "extracted_with_value",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "new",
+            "value" : "oAI can use your current location to answer questions, if you enable Location & Maps access in Settings."
+          }
+        }
+      }
+    },
+    "NSRemindersFullAccessUsageDescription" : {
+      "comment" : "Privacy - Reminders Full Access Usage Description",
+      "extractionState" : "extracted_with_value",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "new",
+            "value" : "oAI can read and create reminders when you ask it to, if you enable Reminders access in Settings."
+          }
+        }
+      }
     }
   },
   "version" : "1.1"