feat(context): enhance timeout handling, tenant isolation, and budget management

- Added timeout enforcement for token counting, scoring, and compression with detailed error handling.
- Introduced tenant isolation in context caching using project and agent identifiers.
- Enhanced budget management with stricter checks for critical context overspending and buffer limitations.
- Optimized per-context locking with cleanup to prevent memory leaks in concurrent environments.
- Updated default assembly timeout settings for improved performance and reliability.
- Improved XML escaping in Claude adapter for safety against injection attacks.
- Standardized token estimation using model-specific ratios.

backend/app/services/context/config.py

@@ -149,10 +149,11 @@ class ContextSettings(BaseSettings):
 
     # Performance settings
     max_assembly_time_ms: int = Field(
-        default=100,
+        default=2000,
         ge=10,
-        le=5000,
-        description="Maximum time for context assembly in milliseconds",
+        le=30000,
+        description="Maximum time for context assembly in milliseconds. "
+        "Should be high enough to accommodate MCP calls for knowledge retrieval.",
     )
     parallel_scoring: bool = Field(
         default=True,