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>

dss-claude-plugin/core/__init__.py

@@ -2,11 +2,21 @@
 DSS Core Module - Configuration and Context Management.
 
 Extended with Context Compiler for design system context resolution.
+
+Enterprise Architecture:
+- LOCAL mode: Uses LocalAnalysisCache for fast, offline-capable validation
+- REMOTE mode: Full analysis via API
+- CI mode: Authoritative enforcement, uploads metrics to dashboard
 """
 
 from .compiler import EMERGENCY_SKIN, ContextCompiler
 from .config import DSSConfig, DSSMode
 from .context import DSSContext
+from .local_cache import (
+    LocalAnalysisCache,
+    LocalCacheValidator,
+    get_project_cache,
+)
 from .mcp_extensions import (
     COMPILER,
     get_active_context,
@@ -23,6 +33,9 @@ __all__ = [
     "DSSContext",
     "ContextCompiler",
     "EMERGENCY_SKIN",
+    "LocalAnalysisCache",
+    "LocalCacheValidator",
+    "get_project_cache",
     "get_active_context",
     "resolve_token",
     "validate_manifest",