feat(jobs): embed.text worker (Ollama → vector(1024))

Pads nomic-embed-text's 768 dims to 1024 zeros so a later 1024-dim model
swap is a re-embed, not a migration (per master spec).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/jobs/index.js

@@ -2,8 +2,9 @@ import * as queue from './queue.js';
 import * as echo from './workers/echo.js';
 import * as url from './workers/url.js';
 import * as blob from './workers/blob.js';
+import * as embed from './workers/embed.js';
 
-const WORKERS = [echo, url, blob];
+const WORKERS = [echo, url, blob, embed];
 
 export async function registerWorkers() {
   for (const w of WORKERS) {