Fix collision resolver: sync ID counters before remapping

The collision resolver was failing when remapping issues to new IDs because
the issue_counters table was out of sync with actual database IDs. Test issues
(bd-200 through bd-312) were created without updating the counter, causing
UNIQUE constraint violations when --resolve-collisions tried to use those IDs.

Added SyncAllCounters() call before remapping to ensure counters reflect all
existing issues in the database. This prevents ID collisions during import.

Fixes the core functionality needed for multi-device git-based sync (bd-271).

Amp-Thread-ID: https://ampcode.com/threads/T-a2a94e1b-b220-41b0-bf7d-f2640a44292b
Co-authored-by: Amp <amp@ampcode.com>

internal/storage/sqlite/collision.go

@@ -244,6 +244,11 @@ func countReferences(issueID string, allIssues []*types.Issue, allDeps map[strin
 func RemapCollisions(ctx context.Context, s *SQLiteStorage, collisions []*CollisionDetail, allIssues []*types.Issue) (map[string]string, error) {
 	idMapping := make(map[string]string)
 
+	// Sync counters before remapping to avoid ID collisions
+	if err := s.SyncAllCounters(ctx); err != nil {
+		return nil, fmt.Errorf("failed to sync ID counters: %w", err)
+	}
+
 	// For each collision (in order of ascending reference score)
 	for _, collision := range collisions {
 		oldID := collision.ID