fix: Resolve 11 errcheck linter violations to unblock CI (bd-91)

Fixed all unchecked error returns in production code:
- os.Remove() calls in cleanup paths
- cmd.Wait() in goroutines
- fmt.Fprintf() writes
- Type assertions with proper ok checks

Reduces linter issues from 99 to 88. CI should now pass linting.

.beads/beads.jsonl

@@ -1,6 +1,9 @@
 {"id":"bd-1","title":"Global daemon should warn/reject --auto-commit and --auto-push","description":"When user runs 'bd daemon --global --auto-commit', it's unclear which repo the daemon will commit to (especially after fixing bd-77 where global daemon won't open a DB).\n\nOptions:\n1. Warn and ignore the flags in global mode\n2. Error out with clear message\n\nLine 87-91 already checks autoPush, but should skip check entirely for global mode. Add user-friendly messaging about flag incompatibility.","status":"closed","priority":3,"issue_type":"feature","created_at":"2025-10-21T23:53:44.31362-07:00","updated_at":"2025-10-23T19:33:21.069816-07:00","closed_at":"2025-10-17T23:04:30.223432-07:00"}
 {"id":"bd-10","title":"Test issue 1","description":"","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-21T23:53:44.31362-07:00","updated_at":"2025-10-23T19:33:21.070787-07:00","closed_at":"2025-10-21T22:06:41.25599-07:00","labels":["test-label"]}
 {"id":"bd-100","title":"Fix flaky TestMetricsSnapshot/memory_stats on Linux","description":"Linux CI test TestMetricsSnapshot/memory_stats fails with \"Expected non-zero memory allocation\". Appears to be a flaky test - metrics_test.go:168.","design":"Add retry logic or wait for GC stats to populate, or adjust test expectations for timing.","status":"open","priority":2,"issue_type":"bug","created_at":"2025-10-24T09:28:17.98305-07:00","updated_at":"2025-10-24T09:28:17.98305-07:00"}
+{"id":"bd-101","title":"Investigate GH#144: FOREIGN KEY regression in v0.16.0","description":"v0.16.0 introduced FOREIGN KEY constraint error when closing issues via MCP (daemon mode). CLI works fine.\n\n**Key Finding**: Only change between v0.15.0 and v0.16.0 that could affect FK behavior is:\n- modernc.org/sqlite bumped from 1.38.2 to 1.39.1 (commit fbe63bf)\n\n**Evidence**:\n- User reports v0.15.0 worked perfectly (Oct 24, 04:35 UTC)\n- v0.16.0 fails with 'constraint failed: FOREIGN KEY constraint failed (787)'\n- Error occurs in both close() tool and update(status=closed) smart routing\n- CLI 'bd close' works fine, only MCP/daemon fails\n- No changes to CloseIssue() implementation between versions\n- No changes to schema or RPC server handlers\n\n**Next Steps**:\n1. Test downgrading sqlite to 1.38.2\n2. Check modernc.org/sqlite changelog for FK-related changes\n3. Reproduce locally with MCP\n4. If sqlite is the culprit, either fix or pin version\n\n**Related**: GH #144","status":"closed","priority":0,"issue_type":"bug","created_at":"2025-10-24T11:24:39.423407-07:00","updated_at":"2025-10-24T11:49:16.683734-07:00","closed_at":"2025-10-24T11:49:16.683734-07:00"}
+{"id":"bd-102","title":"Test FK regression fix","description":"","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-24T11:25:36.132893-07:00","updated_at":"2025-10-24T11:25:38.270206-07:00","closed_at":"2025-10-24T11:25:38.270206-07:00"}
+{"id":"bd-103","title":"Investigate and upgrade to modernc.org/sqlite 1.39.1+","description":"We had to pin modernc.org/sqlite to v1.38.2 due to a FOREIGN KEY constraint regression in v1.39.1 (SQLite 3.50.4).\n\n**Issue:** bd-101, GH #144\n\n**Symptom:** CloseIssue fails with \"FOREIGN KEY constraint failed (787)\" when called via MCP/daemon, but works fine via CLI.\n\n**Root Cause:** Unknown - likely stricter FK enforcement in SQLite 3.50.4 or modernc.org wrapper changes.\n\n**Workaround:** Pinned to v1.38.2 (SQLite 3.49.x)\n\n**TODO:**\n1. Monitor modernc.org/sqlite releases for fixes\n2. Check SQLite 3.50.5+ changelogs for FK-related fixes\n3. Investigate why daemon mode fails but CLI succeeds (connection reuse? transaction isolation?)\n4. Consider filing upstream issue with reproducible test case\n5. Upgrade when safe","status":"open","priority":2,"issue_type":"task","created_at":"2025-10-24T11:49:12.836292-07:00","updated_at":"2025-10-24T11:49:12.836292-07:00","dependencies":[{"issue_id":"bd-103","depends_on_id":"bd-101","type":"discovered-from","created_at":"2025-10-24T11:49:12.837526-07:00","created_by":"daemon"}]}
 {"id":"bd-11","title":"Add merged_into field to database schema","description":"Add merged_into field to Issue struct and update database schema to support merge tracking","notes":"Simplified: no schema field needed. Close merged issues with reason 'Merged into bd-X'. See bd-79 design.","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-21T23:53:44.31362-07:00","updated_at":"2025-10-23T19:33:21.071139-07:00","closed_at":"2025-10-22T01:07:14.145014-07:00"}
 {"id":"bd-12","title":"Update export/import for merge fields","description":"Include merged_into in JSONL export format. Handle merge relationships on import.","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-21T23:53:44.31362-07:00","updated_at":"2025-10-23T19:33:21.071498-07:00","closed_at":"2025-10-22T01:07:14.146226-07:00"}
 {"id":"bd-13","title":"Implement text reference scanning and replacement","description":"Scan all issues for text references to merged IDs (bd-X patterns) and update to target ID. Reuse logic from import collision resolution.","status":"closed","priority":1,"issue_type":"task","created_at":"2025-10-21T23:53:44.31362-07:00","updated_at":"2025-10-23T19:33:21.071811-07:00","closed_at":"2025-10-22T01:07:04.718151-07:00"}