fix(presence): heartbeat self-heals when worker record disappears

Previously, if the ClaudeWorker record vanished (deleted by
prisma_workers_cleanup, manual cleanup, or a race during shutdown of a
parallel worker), the heartbeat would log a warning and stop itself
permanently. From that moment the NavBar showed 'Geen agent' for the
rest of the MCP-server process lifetime — even though the agent was
still alive and serving tools.

Fix: on result.count === 0, call registerWorker again so the record is
re-created. Heartbeat keeps ticking. Self-healing instead of self-
terminating.

startHeartbeat now also accepts userId (needed for re-registration);
caller in index.ts updated.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/index.ts

@@ -68,7 +68,7 @@ async function main() {
   // is up, regardless of when the MCP client sends its first request.
   const auth = await getAuth()
   await registerWorker({ userId: auth.userId, tokenId: auth.tokenId })
-  const { stop: stopHeartbeat } = startHeartbeat({ tokenId: auth.tokenId })
+  const { stop: stopHeartbeat } = startHeartbeat({ userId: auth.userId, tokenId: auth.tokenId })
   registerShutdownHandlers({ userId: auth.userId, tokenId: auth.tokenId, stopHeartbeat })
 
   const transport = new StdioServerTransport()

src/presence/heartbeat.ts

@@ -1,6 +1,8 @@
 import { prisma } from '../prisma.js'
+import { registerWorker } from './worker.js'
 
 export function startHeartbeat(opts: {
+  userId: string
   tokenId: string
   intervalMs?: number
 }): { stop: () => void } {
@@ -11,11 +13,18 @@ export function startHeartbeat(opts: {
         data: { last_seen_at: new Date() },
       })
       if (result.count === 0) {
-        console.error('[scrum4me-mcp] Heartbeat: worker record not found — token may be revoked. Stopping.')
-        clearInterval(timer)
+        // Record disappeared — likely deleted by prisma_workers_cleanup,
+        // a manual cleanup, or a race during shutdown of a parallel worker.
+        // Re-register so the UI's 'Agent verbonden'-indicator self-heals
+        // instead of going dark for the rest of the process lifetime.
+        try {
+          await registerWorker({ userId: opts.userId, tokenId: opts.tokenId })
+        } catch (err) {
+          console.error('[scrum4me-mcp] Heartbeat: re-register failed', err)
+        }
       }
     } catch {
-      // non-fatal
+      // non-fatal — next tick retries
     }
   }, opts.intervalMs ?? 5_000)