add configurable max_tokens per AI activity

Allows users to configure the max_tokens sent to the AI endpoint for
each activity (tagging, description, extraction, translation) individually,
with per-library overrides following the same pattern as model overrides.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/ai-settings/library/[id]/route.ts

@@ -38,6 +38,10 @@ export async function PUT(
     promptTagger: typeof body.promptTagger === 'string' ? body.promptTagger : undefined,
     promptExtract: typeof body.promptExtract === 'string' ? body.promptExtract : undefined,
     promptTranslate: typeof body.promptTranslate === 'string' ? body.promptTranslate : undefined,
+    maxTokensTag: typeof body.maxTokensTag === 'number' ? body.maxTokensTag : (body.maxTokensTag === null ? null : undefined),
+    maxTokensDescribe: typeof body.maxTokensDescribe === 'number' ? body.maxTokensDescribe : (body.maxTokensDescribe === null ? null : undefined),
+    maxTokensExtract: typeof body.maxTokensExtract === 'number' ? body.maxTokensExtract : (body.maxTokensExtract === null ? null : undefined),
+    maxTokensTranslate: typeof body.maxTokensTranslate === 'number' ? body.maxTokensTranslate : (body.maxTokensTranslate === null ? null : undefined),
   })
 
   return NextResponse.json(getLibraryAiOverrides(id))

src/app/api/ai-settings/route.ts

@@ -30,6 +30,10 @@ export async function PUT(request: NextRequest) {
     promptExtract?: string
     promptTranslate?: string
     maxRetries?: number
+    maxTokensTag?: number
+    maxTokensDescribe?: number
+    maxTokensExtract?: number
+    maxTokensTranslate?: number
   }
   try {
     body = await request.json()
@@ -42,6 +46,7 @@ export async function PUT(request: NextRequest) {
     modelTagging, modelDescribe, modelExtract, modelTranslate,
     promptDescribe, promptTagger, promptExtract, promptTranslate,
     maxRetries,
+    maxTokensTag, maxTokensDescribe, maxTokensExtract, maxTokensTranslate,
   } = body
 
   if (typeof endpoint !== 'string') {
@@ -66,6 +71,10 @@ export async function PUT(request: NextRequest) {
     typeof promptTagger === 'string' ? promptTagger : undefined,
     typeof promptExtract === 'string' ? promptExtract : undefined,
     typeof promptTranslate === 'string' ? promptTranslate : undefined,
+    typeof maxTokensTag === 'number' ? maxTokensTag : undefined,
+    typeof maxTokensDescribe === 'number' ? maxTokensDescribe : undefined,
+    typeof maxTokensExtract === 'number' ? maxTokensExtract : undefined,
+    typeof maxTokensTranslate === 'number' ? maxTokensTranslate : undefined,
   )
 
   if (typeof preferredLanguage === 'string' && preferredLanguage.trim()) {