feat(tools): add image generation via Google AI Imagen 3

output: /mnt/work/tmp/image-gen/
triggered by !pic <prompt> in discord

src/tools/image-gen.ts

@@ -0,0 +1,70 @@
+/**
+ * Image generation tool using Google AI (Imagen 3).
+ * Usage: bun run src/tools/image-gen.ts "prompt here"
+ * Outputs the path to the generated image.
+ */
+
+const API_KEY = process.env.GOOGLE_AI_API_KEY;
+const OUTPUT_DIR = '/mnt/work/tmp/image-gen';
+const MODEL = 'imagen-3.0-generate-002';
+
+async function generateImage(prompt: string): Promise<string> {
+  if (!API_KEY) throw new Error('Missing GOOGLE_AI_API_KEY in .env');
+
+  console.error(`Generating: "${prompt}"...`);
+
+  const res = await fetch(
+    `https://generativelanguage.googleapis.com/v1beta/models/${MODEL}:predict?key=${API_KEY}`,
+    {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        instances: [{ prompt }],
+        parameters: {
+          sampleCount: 1,
+          aspectRatio: '1:1',
+          safetyFilterLevel: 'block_few',
+        },
+      }),
+      signal: AbortSignal.timeout(60_000),
+    }
+  );
+
+  if (!res.ok) {
+    const text = await res.text();
+    throw new Error(`API error ${res.status}: ${text}`);
+  }
+
+  const data = await res.json();
+  const b64 = data.predictions?.[0]?.bytesBase64Encoded;
+
+  if (!b64) {
+    throw new Error(`No image in response: ${JSON.stringify(data).slice(0, 500)}`);
+  }
+
+  const { mkdirSync, writeFileSync } = await import('fs');
+  mkdirSync(OUTPUT_DIR, { recursive: true });
+
+  const filename = `img_${Date.now()}.png`;
+  const outPath = `${OUTPUT_DIR}/${filename}`;
+  writeFileSync(outPath, Buffer.from(b64, 'base64'));
+
+  console.error(`Saved: ${outPath}`);
+  return outPath;
+}
+
+async function main() {
+  const prompt = process.argv.slice(2).join(' ');
+  if (!prompt) {
+    console.error('Usage: bun run src/tools/image-gen.ts "prompt here"');
+    process.exit(1);
+  }
+
+  const path = await generateImage(prompt);
+  console.log(path);
+}
+
+main().catch(e => {
+  console.error(e);
+  process.exit(1);
+});