feat(app): add crash visibility, memory relief, and clipboard reply work

Squashes the working tree that had accumulated on cloud-agent. Two
strands of work, kept in one commit at the maintainer's request.

Crash and stability (this session):

- Subscribe to MetricKit so crash, hang, CPU, and disk-write diagnostics
  are recorded on device. Keyboard-extension memory kills are the most
  likely way a user loses the keyboard mid-sentence and iOS does not
  classify them as crashes, so they never reach App Store Connect.
- Upload those reports to POST /v1/analytics/diagnostics from internal
  builds only (local Debug and TestFlight), reusing the analytics
  installation identifier and skipping entirely when analytics are off.
  App Store builds keep everything on device.
- Shed the Chinese engine, English lexicon, and in-flight pipeline work
  at the 40 MiB and 48 MiB budget thresholds instead of waiting for a
  system memory warning that jetsam often preempts.
- Install audio taps with the input node's live format through one
  shared adaptive resampler, so an audio-route change mid-recording no
  longer raises an uncatchable format-mismatch exception. Covers the
  dictation preview and the Mac recorder, which still used the pattern
  the Flow capture path had already moved away from.
- Harden the librime bridge: never pass a nil string across a nonnull
  boundary when a user dictionary holds malformed UTF-8, null-check the
  engine API vector, and distrust a candidate count without its array.
- Guard the expanded candidate grid against a list that shrinks while
  the collection view is still laying out against the previous count.
- Resolve localized text without the App Group so the screen shown when
  that container is missing renders its message instead of crashing on
  launch, which is the one situation it exists to handle.
- Gate CI on the App Group and Keychain wiring that the keyboard
  extension hard-depends on, with a self-test proving the check fails.

Clipboard, reply, and semantics (pre-existing working tree):

- Unify the reply center, refresh keyboard AI features, and add native
  event and reminder exporters.
- Expand clipboard semantic routing with authored corpora and a
  product-blind holdout, plus the scripts that build and validate them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

OSGKeyboard/Services/AppPermissions.swift

@@ -86,10 +86,53 @@ enum AppPermissions {
         }
     }
 
+    /// Undocumented Settings deep link that lands on General → Keyboard, the
+    /// page where the user adds the keyboard and grants Full Access.
+    ///
+    /// `prefs:`-family URLs are private. App Review generally rejects them,
+    /// with custom-keyboard extensions using this specific keyboard path as
+    /// the long-standing exception — it is what shipping third-party keyboards
+    /// rely on. Apple can break or start rejecting it at any time, so every
+    /// call falls back to the public `openSettingsURLString`, and setting this
+    /// to `false` removes the private scheme from the binary's behaviour
+    /// entirely without touching any call site.
+    static let usesPrivateKeyboardSettingsDeepLink = false
+
+    private static let keyboardSettingsDeepLink = "App-Prefs:root=General&path=Keyboard"
+
+    /// Opens the keyboard section of Settings when iOS honours the deep link,
+    /// otherwise the app's own Settings page. `completion` reports whether any
+    /// of the attempts was accepted, so the caller can fall back to written
+    /// steps when none was.
     @MainActor
-    static func openSystemSettings() {
-        guard let url = URL(string: UIApplication.openSettingsURLString) else { return }
-        UIApplication.shared.open(url)
+    static func openKeyboardSettings(completion: ((Bool) -> Void)? = nil) {
+        guard usesPrivateKeyboardSettingsDeepLink,
+              let deepLink = URL(string: keyboardSettingsDeepLink) else {
+            openSystemSettings(completion: completion)
+            return
+        }
+        UIApplication.shared.open(deepLink) { opened in
+            guard opened else {
+                openSystemSettings(completion: completion)
+                return
+            }
+            completion?(true)
+        }
+    }
+
+    /// Opens the app's own page in Settings. iOS exposes no *public* URL that
+    /// reaches General → Keyboard → Keyboards, so callers must still guide the
+    /// user through the remaining taps. `completion` reports whether iOS
+    /// actually accepted the open so the caller can fall back to written steps.
+    @MainActor
+    static func openSystemSettings(completion: ((Bool) -> Void)? = nil) {
+        guard let url = URL(string: UIApplication.openSettingsURLString) else {
+            completion?(false)
+            return
+        }
+        UIApplication.shared.open(url) { opened in
+            completion?(opened)
+        }
     }
 
     /// Performs an explicit direct read so iOS can present paste authorization