fix: cli improvements (embed --db, DB locking, prerelease check, build logging)

- Add missing --db flag to `embed` command, passing customDbPath to buildEmbeddings
- Add busy_timeout pragma (5s) and advisory lockfile to openDb/closeDb for concurrent access safety
- Suppress update-check notifications for prerelease/dev versions (contains '-')
- Log changed/removed file names at debug level during incremental builds

Impact: 1 functions changed, 0 affected

Author: github-actions[bot]

src/builder.js

@@ -442,7 +442,8 @@ export async function buildGraph(rootDir, opts = {}) {
     );
   } else {
     info(`Incremental: ${parseChanges.length} changed, ${removed.length} removed`);
-    if (parseChanges.length > 0) debug(`Changed files: ${parseChanges.map((c) => c.relPath).join(', ')}`);
+    if (parseChanges.length > 0)
+      debug(`Changed files: ${parseChanges.map((c) => c.relPath).join(', ')}`);
     if (removed.length > 0) debug(`Removed files: ${removed.join(', ')}`);
     // Remove embeddings/metrics/edges/nodes for changed and removed files
     // Embeddings must be deleted BEFORE nodes (we need node IDs to find them)