feat: Enterprise DSS architecture implementation

Complete implementation of enterprise design system validation:

Phase 1 - @dss/rules npm package:
- CLI with validate and init commands
- 16 rules across 5 categories (colors, spacing, typography, components, a11y)
- dss-ignore support (inline and next-line)
- Break-glass [dss-skip] for emergency merges
- CI workflow templates (Gitea, GitHub, GitLab)

Phase 2 - Metrics dashboard:
- FastAPI metrics API with SQLite storage
- Portfolio-wide metrics aggregation
- Project drill-down with file:line:column violations
- Trend charts and history tracking

Phase 3 - Local analysis cache:
- LocalAnalysisCache for offline-capable validation
- Mode detection (LOCAL/REMOTE/CI)
- Stale cache warnings with recommendations

Phase 4 - Project onboarding:
- dss-init command for project setup
- Creates ds.config.json, .dss/ folder structure
- Updates .gitignore and package.json scripts
- Optional CI workflow setup

Architecture decisions:
- No commit-back: CI uploads to dashboard, not git
- Three-tier: Dashboard (read-only) → CI (authoritative) → Local (advisory)
- Pull-based rules via npm for version control

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

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

apps/api/server.py

@@ -32,6 +32,7 @@ from fastapi.staticfiles import StaticFiles
 from pydantic import BaseModel
 
 from apps.api.browser_logger import router as browser_log_router
+from apps.api.metrics import router as metrics_router
 from dss import settings
 
 # Load environment variables from .env file FIRST (before any other imports)
@@ -313,6 +314,9 @@ app.add_middleware(
 # Include browser logger router for console log forwarding
 app.include_router(browser_log_router)
 
+# Include metrics router for CI pipeline uploads and dashboard
+app.include_router(metrics_router)
+
 # Mount Admin UI static files
 UI_DIR = Path(__file__).parent.parent.parent / "admin-ui"
 if UI_DIR.exists():