fix(tests): Improve HACS unavailability detection for rate limits

**Problem:**
- `test_install_mcp_tools_basic` was failing with INTERNAL_ERROR when GitHub rate limited
- Other HACS tests were properly skipped with "rate_limit" detection
- The `is_hacs_unavailable()` helper didn't recognize nested error dicts or INTERNAL_ERROR + rate limit

**Solution:**
- Handle nested error dict structure: `{'code': 'INTERNAL_ERROR', 'message': '...'}`
- Add detection for `INTERNAL_ERROR` combined with "rate" or "github" keywords
- Add broader "rate limit" text detection

**Impact:**
- HACS tests will now properly skip when GitHub rate limits occur
- Reduces flaky test failures in CI
- Consistent with how other HACS tests handle rate limiting

Fixes the failing CI check on ubuntu-latest.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: julienld

tests/src/e2e/workflows/hacs/test_hacs.py

@@ -45,13 +45,22 @@ def is_hacs_unavailable(data: dict) -> tuple[bool, str]:
     """
     error = data.get("error", "")
     error_code = data.get("error_code", "")
+    error_str = str(error).lower()
+
+    # Handle nested error dict structure
+    if isinstance(error, dict):
+        error_code = error.get("code", error_code)
+        error_str = str(error.get("message", "")).lower()
 
     unavailable_indicators = [
         (error_code == "HACS_NOT_AVAILABLE", "HACS not available"),
         (error_code == "HACS_DISABLED", f"HACS disabled: {data.get('disabled_reason', 'unknown')}"),
-        ("not found" in str(error).lower(), "Command not found"),
-        ("unknown command" in str(error).lower(), "Unknown command"),
-        ("disabled" in str(error).lower(), "HACS disabled"),
+        (error_code == "INTERNAL_ERROR" and "rate" in error_str, "GitHub rate limit"),
+        (error_code == "INTERNAL_ERROR" and "github" in error_str, "GitHub access issue"),
+        ("not found" in error_str, "Command not found"),
+        ("unknown command" in error_str, "Unknown command"),
+        ("disabled" in error_str, "HACS disabled"),
+        ("rate" in error_str and "limit" in error_str, "GitHub rate limit"),
         ("401" in str(error), "GitHub authentication failed"),
     ]