feat: add project-review workflow (whole-project / single-feature review)

Adds the project-review workflow for code review independent of the git
diff. The scope is parsed from the user instruction: 全面/整个项目 ->
whole-project (score every source file), otherwise feature + target
keyword (locate the code with semantic search + graph queries).

- scoring_tools.py: score_review_func gains all_files=True to score every
  source file in the graph via store.get_all_files()
- main.py: score_review_tool gains all_files param; registers the
  project_review MCP prompt (prompts 6->7)
- prompts.py: project_review_prompt(scope, target) with whole-project and
  feature branches (fixed a precedence bug that truncated the feature text)
- skills.py + skills/project-review/: new read-only project-review skill
  with shared checklists
- .opencode/command/code-review-graph-project-review.md: slash command
- tests: test_project_review.py (prompt rendering), TestProjectReviewPrompt,
  skill count assertions 5->6, all_files wiring checks
- docs: prompts (6->7) + project-review entries across COMMANDS, CLAUDE,
  README (+localized), INDEX, architecture, LLM-OPTIMIZED-REFERENCE,
  CHANGELOG

docs/INDEX.md

@@ -3,7 +3,7 @@
 - [USAGE.md](USAGE.md) -- How to install and use
 - [FAQ.md](FAQ.md) -- How it compares to LSP, RAG, grep, and similar tools; when not to use it
 - [FEATURES.md](FEATURES.md) -- What's included, changelog
-- [COMMANDS.md](COMMANDS.md) -- All 31 MCP tools, 6 MCP prompts, skills, and CLI commands
+- [COMMANDS.md](COMMANDS.md) -- All 31 MCP tools, 7 MCP prompts, skills, and CLI commands
 - [GITHUB_ACTION.md](GITHUB_ACTION.md) -- Risk-scored PR review comments via GitHub Actions
 - [CUSTOM_LANGUAGES.md](CUSTOM_LANGUAGES.md) -- Bring your own language via `.code-review-graph/languages.toml`
 - [LLM-OPTIMIZED-REFERENCE.md](../code_review_graph/docs/LLM-OPTIMIZED-REFERENCE.md) -- Token-optimized reference for MCP-capable AI coding agents