Fix enum34 error by excluding it in PyInstaller spec

The previous approach of uninstalling enum34 before PyInstaller didn't
work because 'uv run' re-syncs dependencies. The proper solution is to
exclude enum34 directly in the PyInstaller spec file.

Changes:
- Added hooks/hook-enum34.py: Custom PyInstaller hook to exclude enum34
- Updated local-transcription.spec:
  - Added 'hooks' to hookspath
  - Added 'enum34' to excludes list
- Updated build.sh and build.bat:
  - Removed enum34 uninstall step (no longer needed)
  - Added comment explaining enum34 is excluded in spec

Why this works:
- PyInstaller's excludes list prevents enum34 from being bundled
- The custom hook provides documentation and explicit exclusion
- enum34 can remain installed in venv (won't break anything)
- Works regardless of 'uv run' re-syncing dependencies

enum34 is an obsolete Python 2.7/3.3 backport that's incompatible with
PyInstaller and unnecessary on Python 3.4+ (enum is in stdlib).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

local-transcription.spec

@@ -129,10 +129,10 @@ a = Analysis(
     binaries=binaries,
     datas=datas,
     hiddenimports=hiddenimports,
-    hookspath=[],
+    hookspath=['hooks'],  # Add hooks directory for custom PyInstaller hooks
     hooksconfig={},
     runtime_hooks=[],
-    excludes=[],
+    excludes=['enum34'],  # Exclude enum34 - incompatible with PyInstaller and Python 3.4+
     win_no_prefer_redirects=False,
     win_private_assemblies=False,
     cipher=block_cipher,