fix: correct tool count (596), default English dashboard, clean up stale references

- Tool count corrected: 589→596 (was missing 4 OAuth + 4 system config tools)
- System tools: 17→24 (accurate count of @mcp.tool() functions)
- Dashboard defaults to English; Farsi only via ?lang=fa query param
- Updated across all files: README, CLAUDE.md, CONTRIBUTING, DOCKER_README,
  getting-started, CHANGELOG, endpoints config
- Removed remaining Phase references from server.py startup log
- Tests: 289 passing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/endpoints/config.py

@@ -107,7 +107,7 @@ ENDPOINT_CONFIGS = {
         allowed_scopes={"admin"},
         max_tools=400,
     ),
-    # System endpoint - system tools only (17 tools) - Phase X.3
+    # System endpoint - system tools only (24 tools)
     # For API key management, OAuth, rate limiting without loading all plugins
     EndpointType.SYSTEM: EndpointConfig(
         path="/system",