fix(mcp): cap codegraph_context output to prevent context bloat (#296)

Route handleContext's output through the shared truncateOutput cap
(MAX_OUTPUT_LENGTH) so codegraph_context can no longer blow past the context
budget — every sibling MCP tool already truncates; this was the one uncapped
output path.

Closes #296

Co-authored-by: Baijack-star <71923891+Baijack-star@users.noreply.github.com>

src/mcp/tools.ts

@@ -775,11 +775,11 @@ export class ToolHandler {
 
     // buildContext returns string when format is 'markdown'
     if (typeof context === 'string') {
-      return this.textResult(context + reminder);
+      return this.textResult(this.truncateOutput(context + reminder));
     }
 
     // If it returns TaskContext, format it
-    return this.textResult(this.formatTaskContext(context) + reminder);
+    return this.textResult(this.truncateOutput(this.formatTaskContext(context) + reminder));
   }
 
   /**