fix(sweep): retry on ingest failure, bound sweepWorkflowSeen to active sessions

Address review feedback on the workflow-ingest gate:

- A transient ingest failure previously stuck a session: the fingerprint was
  recorded before the async ingest, so on rejection the session was skipped
  until its artifacts changed again. Delete the fingerprint in .catch so the
  next sweep retries it.
- sweepWorkflowSeen never evicted entries for sessions that went inactive, so
  it grew unbounded over the process lifetime. Prune it to the current active
  set at the start of each sweep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Doccy008

server/index.js

@@ -815,6 +815,12 @@ if (require.main === module) {
     // Catches workflows that complete without a subsequent hook and flips
     // launch-detected "running" rows to "completed" once their journal lands.
     const { ingestWorkflowsForSession, workflowsMaxMtime } = require("./lib/workflow-ingest");
+    // Forget fingerprints for sessions that are no longer active so the map
+    // can't grow without bound over the process lifetime.
+    const activeIds = new Set(active.map((r) => r.session_id));
+    for (const id of sweepWorkflowSeen.keys()) {
+      if (!activeIds.has(id)) sweepWorkflowSeen.delete(id);
+    }
     for (const row of active) {
       if (!row.tp) continue;
       // Skip sessions whose workflow artifacts are unchanged since the last
@@ -839,6 +845,9 @@ if (require.main === module) {
           if (sess) broadcast("session_updated", sess);
         })
         .catch((err) => {
+          // Forget the fingerprint so the next sweep retries this session
+          // instead of skipping it until its artifacts change again.
+          sweepWorkflowSeen.delete(row.session_id);
           console.warn(
             `[SWEEP] Workflow scan failed for session ${row.session_id}:`,
             err?.message || err