test: improve test coverage for domain files from 46-58% to 92-100%

- Add 31 tests for SourceFile.ts (46% → 100%)
- Add 31 tests for ProjectPath.ts (50% → 100%)
- Add 18 tests for ValueObject.ts (25% → 100%)
- Add 32 tests for RepositoryViolation.ts (58% → 92.68%)
- Total test count: 345 → 457 tests (all passing)
- Overall coverage: 95.4% statements, 86.25% branches, 96.68% functions
- Update version to 0.7.7
- Update ROADMAP.md and CHANGELOG.md

packages/guardian/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@samiyev/guardian",
-    "version": "0.7.6",
+    "version": "0.7.7",
     "description": "Research-backed code quality guardian for AI-assisted development. Detects hardcodes, circular deps, framework leaks, entity exposure, and 8 architecture violations. Enforces Clean Architecture/DDD principles. Works with GitHub Copilot, Cursor, Windsurf, Claude, ChatGPT, Cline, and any AI coding tool.",
     "keywords": [
         "puaros",