Step 8: Polish — lint, clock abstraction, e2e test.

- golangci-lint config with errcheck, govet, staticcheck, errorlint
- Fix all lint issues (unchecked error returns in cleanup paths, De Morgan)
- Inject jonboulle/clockwork into Garden for deterministic timestamps
- Add manifest.NewWithTime() for clock-aware initialization
- E2e lifecycle test: init → add → checkpoint → modify → status → restore → verify
- Update CLAUDE.md, PROJECT_PLAN.md, PROGRESS.md

Phase 1 (local) is now complete. All 9 CLI commands implemented and tested.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

store/store.go

@@ -23,7 +23,7 @@ func validHash(s string) bool {
 		return false
 	}
 	for _, c := range s {
-		if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f')) {
+		if (c < '0' || c > '9') && (c < 'a' || c > 'f') {
 			return false
 		}
 	}
@@ -74,17 +74,17 @@ func (s *Store) Write(data []byte) (string, error) {
 	tmpName := tmp.Name()
 
 	if _, err := tmp.Write(data); err != nil {
-		tmp.Close()
-		os.Remove(tmpName)
+		_ = tmp.Close()
+		_ = os.Remove(tmpName)
 		return "", fmt.Errorf("store: write temp file: %w", err)
 	}
 	if err := tmp.Close(); err != nil {
-		os.Remove(tmpName)
+		_ = os.Remove(tmpName)
 		return "", fmt.Errorf("store: close temp file: %w", err)
 	}
 
 	if err := os.Rename(tmpName, p); err != nil {
-		os.Remove(tmpName)
+		_ = os.Remove(tmpName)
 		return "", fmt.Errorf("store: rename blob into place: %w", err)
 	}