feat: switch embeddings from Voyage AI to Google Gemini text-embedding-004

- embedText: call Gemini REST API (768-dim) instead of Voyage (1024-dim)
- Migration: drop+recreate incidents.embedding as vector(768), update
  match_incidents function, swap VOYAGE_API_KEY → GOOGLE_AI_API_KEY in app_settings
- Settings UI: relabel to "Google AI API Key (Embeddings)"
- All call sites updated (incidents POST, similar GET)

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

app/api/incidents/[id]/similar/route.ts

@@ -18,7 +18,7 @@ export async function GET(
   if (!profile || !['hse', 'admin'].includes(profile.role))
     return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
 
-  const voyageKey = await getApiKey(supabase, 'VOYAGE_API_KEY')
+  const googleAiKey = await getApiKey(supabase, 'GOOGLE_AI_API_KEY')
 
   const { data: incident } = await supabase
     .from('incidents')
@@ -34,7 +34,7 @@ export async function GET(
     if (inc.embedding) {
       embeddingVec = JSON.parse(inc.embedding) as number[]
     } else {
-      embeddingVec = await embedText(inc.description, voyageKey)
+      embeddingVec = await embedText(inc.description, googleAiKey)
       // Closed incidents are locked at the DB level — the trigger would reject
       // this backfill. The vector still serves the similarity query below.
       if (inc.status !== 'closed') {

app/api/incidents/route.ts

@@ -182,9 +182,9 @@ export async function POST(request: Request) {
   // Embed description asynchronously for future similarity search
   const supabaseForEmbed = supabase
   import('@/lib/settings').then(({ getApiKey }) =>
-    getApiKey(supabaseForEmbed, 'VOYAGE_API_KEY').then(voyageKey =>
+    getApiKey(supabaseForEmbed, 'GOOGLE_AI_API_KEY').then(googleAiKey =>
       import('@/lib/claude/embed').then(({ embedText }) =>
-        embedText(input.description.trim(), voyageKey).then(embedding =>
+        embedText(input.description.trim(), googleAiKey).then(embedding =>
           supabase.from('incidents').update({
             embedding: `[${embedding.join(',')}]` as unknown as string,
           }).eq('id', incident.id)

app/api/settings/route.ts

@@ -6,7 +6,7 @@ import { createClient } from '@/lib/supabase/server'
 const ALLOWED_KEYS = [
   'ANTHROPIC_API_KEY',
   'DEEPSEEK_API_KEY',
-  'VOYAGE_API_KEY',
+  'GOOGLE_AI_API_KEY',
   'META_WHATSAPP_PHONE_NUMBER_ID',
   'META_WHATSAPP_ACCESS_TOKEN',
 ] as const