chore(version): bump to v1.0.0-rc.8 (post-rc.7 v1 audio + PTT lifecycle work)

pubspec.yaml + _kAppVersion in main.dart were both still reading
v1.0.0-rc.1 even though the branch has accumulated 50+ commits of
post-rc.7 work (the v1 audio + PTT lifecycle redesign in
SDD-094..097, plus DEC-029/030/031). The About dialog and the
diagnostic export's app_version field both surfaced the wrong
string.

Aligned both to v1.0.0-rc.8+59 (build number is the current commit
count on the branch). The Rust workspace version stays at
0.0.1-pre — it's an internal pre-release marker the diagnostic
export carries as crate_version, not user-facing, and changing it
cascades into every inheriting Cargo.toml for no benefit.

The actual v1.0.0-rc.8 tag will land once the Korean Windows 11
human-side P0 acceptance pass closes; this commit aligns the
strings the running build shows so the tester sees a consistent
version while running the tests.

apps/chanora_flutter/lib/main.dart

@@ -24,7 +24,9 @@ import 'widgets/voice_settings.dart';
 
 /// Public version string shown in the About dialog. Aligned with
 /// `pubspec.yaml` and the git tag for the MVP release candidate.
-const String _kAppVersion = 'v1.0.0-rc.1';
+/// Bumped to rc.8 for the post-rc.7 v1 audio + PTT lifecycle work
+/// (SDD-094..097, DEC-029..031).
+const String _kAppVersion = 'v1.0.0-rc.8';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();

apps/chanora_flutter/pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.0.0-rc.1+5
+version: 1.0.0-rc.8+59
 
 environment:
   sdk: ^3.11.5