chore(repo): untrack macOS chanora_bridge.framework build artifacts

The macOS chanora_bridge.framework tree at
apps/chanora_flutter/macos/Frameworks/chanora_bridge.framework was
being tracked in git despite being a pure build artifact. Both
mechanisms in chanora_bridge.podspec rebuild the entire tree from
scratch:

  * prepare_command (runs on `pod install`) — `rm -rf $FW` and
    reconstructs Versions/A, the Versions/Current and Resources
    symlinks, Info.plist, and copies the lipo-merged universal dylib.
  * script_phase :before_compile (runs on every Xcode build) — same
    rm -rf + reconstruction, gated on freshness of the cargo output.

Tracking the tree therefore added zero value and ~36 MB per binary
revision (the chanora_bridge dylib alone). The iOS counterpart at
apps/chanora_flutter/ios/Frameworks/ has been correctly ignored since
.gitignore:118-119 was added; this commit mirrors that rule for macOS.

Changes:
  - git rm --cached -r the 5 tracked entries (binary, 3 symlinks,
    Info.plist). Working tree is untouched, so existing local
    builds keep functioning until the next `pod install` /
    Xcode build refreshes them.
  - Add /apps/chanora_flutter/macos/Frameworks/ to .gitignore
    alongside the existing iOS entry, with a comment pointing at the
    podspec mechanism so the next maintainer understands the rule.

Verified the working tree binary survives the cache untrack and
the path is now matched by .gitignore:125.

.gitignore

@@ -117,6 +117,12 @@ opencode.json
 
 # iOS framework build artifacts produced by chanora_bridge.podspec
 /apps/chanora_flutter/ios/Frameworks/
+
+# macOS framework build artifacts produced by chanora_bridge.podspec
+# (prepare_command + script_phase rm -rf and regenerate this tree on
+# every pod install AND every Xcode build, so tracking it in git is
+# pure waste — the committed binary was ~40 MB per commit).
+/apps/chanora_flutter/macos/Frameworks/
 .opencode/
 AGENTS.md
 Screenshot 2026-05-17 at 22.23.07.png