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/dashboard/routes.py

@@ -157,15 +157,10 @@ DASHBOARD_TRANSLATIONS = {
 
 
 def detect_language(accept_language: str | None, query_lang: str | None = None) -> str:
-    """Detect language from Accept-Language header or query parameter."""
+    """Detect language from query parameter. Default is English."""
     if query_lang and query_lang in DASHBOARD_TRANSLATIONS:
         return query_lang
 
-    if accept_language:
-        # Check for Persian/Farsi
-        if "fa" in accept_language.lower() or "fa-ir" in accept_language.lower():
-            return "fa"
-
     return "en"