fix(hud): version resolution fallback to plugin.json (Wave 1-A)

[JeremyDev87]

Problem

StatusBar shows stale v5.2.0 when the actual plugin version is v5.5.0. Root cause: hud-state.json freezes the version at session-start and is never re-read when the plugin updates.

Fix (Wave 1-A)

Strengthen get_fresh_version() with a deterministic tier-2 fallback:

1. tier 1: installed_plugins.json (global, authoritative after /plugin update)
2. tier 2 (NEW): ../.claude-plugin/plugin.json (local, authoritative for dev installs) — resolved via __file__ relative path
3. tier 3: hud_state.version (last resort, may be stale)

API

New plugin_json_file: Optional[str] = None parameter:

• None (default) — tier-2 disabled, preserves backcompat
• "" — use default dev-install path (production enables this via main())
• non-empty string — test override

Tests

7 new behavior tests in test_hud_version.py:

• Fallback ordering (3 tests)
• Malformed plugin.json skipped
• Missing version key skipped
• Default path resolves to real repo file
• 3 existing tests remain passing (Optional[str]=None default preserves compat)

Acceptance

• 162/162 tests pass (133 Golden Rule + 29 new/updated)
• format_status_line() in production calls with plugin_json_file="" via main()
• Behavior-preserving for callers that don't opt in
• Part of refactor(hud): extract 9 modules for parallel statusbar work #1464 (Wave 0 refactor) effort

Closes the version-display bug reported as "버전도 v5.5.0 인데 v5.2.0 으로 나오고 있어"