fixed knip (**/cache/** dirs are ignored), fixed cache busting when prompt changes

Author: ndbroadbent

src/cache/filesystem.test.ts src/caching/filesystem.test.tssrc/cache/filesystem.test.ts renamed to src/caching/filesystem.test.ts

@@ -194,7 +194,8 @@ describe('generateClassifierCacheKey', () => {
 
   it('should handle empty messages array', () => {
     const key = generateClassifierCacheKey('anthropic', 'claude-haiku-4-5', [])
-    expect(key).toMatch(/^ai\/anthropic\/claude-haiku-4-5\/[a-f0-9]{64}$/)
+    // Format: ai/<provider>/<model>/<promptSig 8 chars>/<hash 64 chars>
+    expect(key).toMatch(/^ai\/anthropic\/claude-haiku-4-5\/[a-f0-9]{8}\/[a-f0-9]{64}$/)
   })
 })
 

src/cache/filesystem.ts src/caching/filesystem.tssrc/cache/filesystem.ts renamed to src/caching/filesystem.ts

@@ -5,6 +5,7 @@
  */
 
 import { createHash } from 'node:crypto'
+import { getPromptSignature } from '../classifier/prompt'
 import type { CacheKeyComponents } from './types'
 
 /**
@@ -65,13 +66,16 @@ export function generateEmbeddingCacheKey(model: string, inputs: readonly string
 
 /**
  * Generate cache key for classification requests.
- * Path: ai/<provider>/<model>/<hash>.json
+ * Path: ai/<provider>/<model>/<promptSig>/<hash>.json
+ *
+ * Includes prompt signature so cache is invalidated when prompt.ts changes.
  */
 export function generateClassifierCacheKey(
   provider: string,
   model: string,
   messages: readonly { readonly content: string; readonly messageId: number }[]
 ): string {
+  const promptSig = getPromptSignature()
   const hash = generateCacheKey({
     service: provider,
     model,
@@ -82,7 +86,7 @@ export function generateClassifierCacheKey(
       }))
     }
   })
-  return `ai/${provider}/${model}/${hash}`
+  return `ai/${provider}/${model}/${promptSig}/${hash}`
 }
 
 /**

src/cache/index.ts src/caching/index.tssrc/cache/index.ts renamed to src/caching/index.ts

@@ -5,8 +5,8 @@
  * and extract activity/location details.
  */
 
-import { generateClassifierCacheKey } from '../cache/key'
-import type { ResponseCache } from '../cache/types'
+import { generateClassifierCacheKey } from '../caching/key'
+import type { ResponseCache } from '../caching/types'
 import {
   type ActivityCategory,
   type CandidateMessage,