feat(auth): restore Google sign-in and AI admin test routes

Google OAuth was implemented locally but never deployed; the login button
only renders when AUTH_GOOGLE_ID and AUTH_GOOGLE_SECRET are set. Also
restores /api/ai/test-* endpoints removed by mistake and wires Google
credentials into deploy workflows.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/app/api/ai/test-chat/route.ts

@@ -0,0 +1,59 @@
+import { NextResponse } from 'next/server'
+import { getChatProvider } from '@/lib/ai/factory'
+import { getSystemConfig } from '@/lib/config'
+import { auth } from '@/auth'
+
+export async function POST() {
+  const session = await auth()
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+  if ((session.user as { role?: string }).role !== 'ADMIN') {
+    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
+  }
+
+  try {
+    const config = await getSystemConfig()
+    const provider = getChatProvider(config)
+
+    const testMessage = 'Reply in exactly 3 words: what is your name?'
+
+    const startTime = Date.now()
+    const response = await provider.generateText(testMessage)
+    const endTime = Date.now()
+
+    if (!response || response.trim().length === 0) {
+      return NextResponse.json(
+        {
+          success: false,
+          error: 'No response from chat provider',
+          provider: config.AI_PROVIDER_CHAT || config.AI_PROVIDER_TAGS || 'ollama',
+          model: config.AI_MODEL_CHAT || 'granite4:latest',
+        },
+        { status: 500 },
+      )
+    }
+
+    return NextResponse.json({
+      success: true,
+      provider: config.AI_PROVIDER_CHAT || config.AI_PROVIDER_TAGS || 'ollama',
+      model: config.AI_MODEL_CHAT || 'granite4:latest',
+      chatResponse: response.trim(),
+      responseTime: endTime - startTime,
+    })
+  } catch (error: unknown) {
+    const config = await getSystemConfig()
+    const message = error instanceof Error ? error.message : 'Unknown error'
+
+    return NextResponse.json(
+      {
+        success: false,
+        error: message,
+        provider: config.AI_PROVIDER_CHAT || config.AI_PROVIDER_TAGS || 'ollama',
+        model: config.AI_MODEL_CHAT || 'granite4:latest',
+        stack: process.env.NODE_ENV === 'development' && error instanceof Error ? error.stack : undefined,
+      },
+      { status: 500 },
+    )
+  }
+}