feat: switch AI provider from Anthropic to DeepSeek

- lib/claude/client.ts: replace Anthropic SDK with openai package pointed at DeepSeek baseURL
- 4 AI routes: port tool definitions, tool_choice, and output parsing to OpenAI function-calling format
- Drop thinking:{type:'adaptive'} (no DeepSeek equivalent); model string → deepseek-chat
- settings/route.ts: add DEEPSEEK_API_KEY to ALLOWED_KEYS
- migration: seed DEEPSEEK_API_KEY placeholder row in app_settings
- tests: update 3 AI route tests to mock createDeepSeekClient + OpenAI response shape

Voyage AI embedding path untouched (DeepSeek has no embeddings endpoint).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CPf5Rc8QPx6V8KLEEgfKEQ

app/api/incidents/ai/quality-check/route.ts

@@ -2,7 +2,7 @@ export const dynamic = 'force-dynamic'
 
 import { NextRequest, NextResponse } from 'next/server'
 import { createClient } from '@/lib/supabase/server'
-import { createAnthropicClient } from '@/lib/claude/client'
+import { createDeepSeekClient } from '@/lib/claude/client'
 import { getApiKey } from '@/lib/settings'
 
 export async function POST(request: NextRequest) {
@@ -20,8 +20,8 @@ export async function POST(request: NextRequest) {
   if ((recentCount ?? 0) > 0)
     return NextResponse.json({ error: 'Rate limited — please wait 60 seconds' }, { status: 429 })
 
-  const anthropicKey = await getApiKey(supabase, 'ANTHROPIC_API_KEY')
-  const anthropic = createAnthropicClient(anthropicKey)
+  const deepseekKey = await getApiKey(supabase, 'DEEPSEEK_API_KEY')
+  const client = createDeepSeekClient(deepseekKey)
 
   let body: { description?: string; incident_type?: string }
   try {
@@ -33,31 +33,33 @@ export async function POST(request: NextRequest) {
     return NextResponse.json({ error: 'description and incident_type required' }, { status: 422 })
   }
 
-  let message: Awaited<ReturnType<typeof anthropic.messages.create>>
+  let res: Awaited<ReturnType<typeof client.chat.completions.create>>
   try {
-    message = await anthropic.messages.create({
-      model: 'claude-opus-4-8',
-      thinking: { type: 'adaptive' },
+    res = await client.chat.completions.create({
+      model: 'deepseek-chat',
       max_tokens: 1024,
       tools: [{
-        name: 'assess_quality',
-        description: 'Assess HSE incident report description quality',
-        input_schema: {
-          type: 'object' as const,
-          properties: {
-            score: { type: 'number', description: '1-10 quality score' },
-            passes: { type: 'boolean', description: 'True when score is 6 or above' },
-            feedback: { type: 'string', description: 'One-sentence quality summary' },
-            suggestions: {
-              type: 'array',
-              items: { type: 'string' },
-              description: 'Up to 3 concrete suggestions to improve the description',
+        type: 'function',
+        function: {
+          name: 'assess_quality',
+          description: 'Assess HSE incident report description quality',
+          parameters: {
+            type: 'object',
+            properties: {
+              score: { type: 'number', description: '1-10 quality score' },
+              passes: { type: 'boolean', description: 'True when score is 6 or above' },
+              feedback: { type: 'string', description: 'One-sentence quality summary' },
+              suggestions: {
+                type: 'array',
+                items: { type: 'string' },
+                description: 'Up to 3 concrete suggestions to improve the description',
+              },
             },
+            required: ['score', 'passes', 'feedback', 'suggestions'],
           },
-          required: ['score', 'passes', 'feedback', 'suggestions'],
         },
       }],
-      tool_choice: { type: 'tool', name: 'assess_quality' },
+      tool_choice: { type: 'function', function: { name: 'assess_quality' } },
       messages: [{
         role: 'user',
         content: `You are an HSE reporting assistant for a Malaysian 3PL warehouse. Assess this incident report description.
@@ -72,17 +74,13 @@ Score 1–10 based on: specificity (location, time, persons involved), completen
     return NextResponse.json({ error: 'AI service unavailable' }, { status: 503 })
   }
 
-  const toolBlock = message.content.find(b => b.type === 'tool_use')
-  if (!toolBlock || toolBlock.type !== 'tool_use') {
-    return NextResponse.json({ error: 'AI assessment failed' }, { status: 500 })
-  }
+  const call = res.choices[0]?.message?.tool_calls?.[0]
+  if (!call || call.type !== 'function') return NextResponse.json({ error: 'AI assessment failed' }, { status: 500 })
+
+  let input: { score?: unknown; passes?: unknown; feedback?: unknown; suggestions?: unknown }
+  try { input = JSON.parse(call.function.arguments) }
+  catch { return NextResponse.json({ error: 'AI returned unexpected structure' }, { status: 500 }) }
 
-  const input = toolBlock.input as {
-    score?: unknown
-    passes?: unknown
-    feedback?: unknown
-    suggestions?: unknown
-  }
   if (
     typeof input.score !== 'number' ||
     typeof input.passes !== 'boolean' ||
@@ -96,7 +94,7 @@ Score 1–10 based on: specificity (location, time, persons involved), completen
     p_table_name: 'incidents',
     p_record_id: user.id,
     p_action: 'ai_quality_check',
-    p_new_value: { score: input.score, passes: input.passes, model: 'claude-opus-4-8' } as never,
+    p_new_value: { score: input.score, passes: input.passes, model: 'deepseek-chat' } as never,
   })
 
   return NextResponse.json(input)