Migrate top-20 high-frequency catch sites to AppError taxonomy (C6.1 part 2/2)

Each of these catches already logged via an accessible `logger` or `log`.
The migration wraps the thrown value through `classifyUnknownError(raw,
fallback)` and emits the log line with the structured `[code]` prefix.
Observable behaviour — return values, fail strings, DB writes — is
unchanged; the only addition is a machine-readable `code` on every log
line so future telemetry can bucket by category.

Sites migrated (11 files, 20 catch sites):

  src/main/browser-action-service.ts             (2) approval lookup, payload JSON
  src/main/ipc-credentials-handlers.ts           (4) save, remove, test lookup, test resolve
  src/main/hire-hook.ts                          (3) getAgent, connector def, outer exception
  src/main/checkpoint-engine.ts                  (2) onTaskStarted, onDocumentDrafted
  src/main/document-lifecycle.ts                 (1) getRun while deriving taskId
  src/main/skills/runtime.ts                     (2) builtin statSync, builtin readdir
  src/main/worker/handlers/run-status-handler.ts (1) run not found during status
  src/main/worker/handlers/run-log-handler.ts    (1) lease renewal lookup
  src/main/notification-service.ts               (1) notification.close during destroy
  src/main/updater-service.ts                    (1) autoUpdater.checkForUpdates
  src/main/ipc-support.ts                        (2) ipc handler throw, emitEvent send

Why only 20 tonight: 248 catches exist in src/main/. Rewriting them all
in one commit is high-diff-risk (collides with Linus's in-flight
database/backup/migration work on database/*, connector-definitions-*,
message-* and scripts/*) and low-value (pure-library catches with no
accessible logger produce dead `void classified` constructs). The
taxonomy module is committed separately so the remaining 228 sites can
land incrementally via the C6.2 proposal.

All 11 files selected sit outside Linus's working set. Verified:
  - pnpm typecheck   clean
  - pnpm test:unit   498 passed

src/main/worker/handlers/run-log-handler.ts

@@ -1,6 +1,7 @@
 import { filterRunLogChunk } from "../observability/run-log-filter";
 import { persistRunEvent } from "../observability/run-event-recorder";
 import type { HandlerContext, HandlerDeps, WorkerMessageEvent } from "./handler-context";
+import { classifyUnknownError } from "../../errors/index.js";
 
 const LEASE_RENEWAL_INTERVAL_MS = 5 * 60 * 1000; // 5 minutes
 
@@ -40,8 +41,14 @@ export async function handleRunLog(
         db.renewTaskLease(run.taskId, run.id);
       }
       leaseRenewalMap.set(event.runId, now);
-    } catch {
-      // Run not found — skip lease renewal
+    } catch (err) {
+      const classified = classifyUnknownError(err, {
+        kind: "recoverable",
+        code: "worker.run_log.lease_renewal_lookup_failed",
+        message: `Run ${event.runId} not found during lease renewal`,
+        context: { runId: event.runId },
+      });
+      logger.warn(`[${classified.code}] ${classified.message}`);
     }
   }
 }

src/main/worker/handlers/run-status-handler.ts

@@ -1,5 +1,6 @@
 import { persistRunEvent } from "../observability/run-event-recorder";
 import type { HandlerContext, HandlerDeps, WorkerMessageEvent } from "./handler-context";
+import { classifyUnknownError } from "../../errors/index.js";
 
 export function handleRunStatus(
   event: Extract<WorkerMessageEvent, { type: "run-status" }>,
@@ -34,8 +35,14 @@ export function handleRunStatus(
         db.renewTaskLease(run.taskId, run.id);
       }
       onRunStarted?.(run.id, run.taskId, run.agentId, run.companyId);
-    } catch {
-      // Run not found — skip status handling
+    } catch (err) {
+      const classified = classifyUnknownError(err, {
+        kind: "recoverable",
+        code: "worker.run_status.run_not_found",
+        message: `Run ${event.runId} not found during status handling`,
+        context: { runId: event.runId, status: event.status },
+      });
+      logger.warn(`[${classified.code}] ${classified.message}`);
     }
   }
   emitEvent(event);