# Task ID: 47

**Title:** Implement session state management for gating

**Status:** done

**Dependencies:** 39 ✓

**Priority:** high

**Description:** Extend the McpRouter to track per-session gating state including gated status, accumulated tags, and retrieved prompts set.

**Details:**

1. Update `/src/mcplocal/src/router.ts` to add session state:
   ```typescript
   interface SessionState {
     gated: boolean;           // starts true if project is gated
     tags: string[];           // accumulated from begin_session + read_prompts
     retrievedPrompts: Set<string>;  // prompts already sent (avoid duplicates)
   }
   
   export class McpRouter {
     private sessionStates: Map<string, SessionState> = new Map();
     
     getSessionState(sessionId: string): SessionState {
       if (!this.sessionStates.has(sessionId)) {
         this.sessionStates.set(sessionId, {
           gated: this.projectConfig?.gated ?? true,
           tags: [],
           retrievedPrompts: new Set(),
         });
       }
       return this.sessionStates.get(sessionId)!;
     }
     
     ungateSession(sessionId: string): void {
       const state = this.getSessionState(sessionId);
       state.gated = false;
     }
     
     addRetrievedPrompts(sessionId: string, names: string[]): void {
       const state = this.getSessionState(sessionId);
       names.forEach(n => state.retrievedPrompts.add(n));
     }
   }
   ```

2. Clean up session state when session closes

3. Handle session state for non-gated projects (gated=false from start)

**Test Strategy:**

- Unit test: New session starts with gated=true for gated project
- Unit test: New session starts with gated=false for non-gated project
- Unit test: ungateSession changes gated to false
- Unit test: addRetrievedPrompts adds to set
- Unit test: retrievedPrompts prevents duplicates
- Unit test: Session state isolated per sessionId
- Unit test: Session cleanup removes state