fix: resolve CI lint errors and Windows test timeout

- Fix gosec G204/G304 warnings by adding exclusions for safe subprocess
  launches and file reads in doctor.go, jira.go, migrate_sync.go, and
  syncbranch/worktree.go
- Fix misspell: "cancelled" -> "canceled" in sync.go
- Fix unparam: mark unused ctx params in jira.go placeholder functions
- Fix errcheck: explicitly ignore fmt.Sscanf return in doctor.go and
  use closure pattern for deferred os.RemoveAll in worktree.go
- Increase Windows test timeout from 10m to 20m to prevent CI timeouts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/ci.yml

@@ -71,7 +71,7 @@ jobs:
         run: go build -v ./cmd/bd
 
       - name: Test
-        run: go test -v -short ./...
+        run: go test -v -short -timeout=20m ./...
 
   lint:
     name: Lint