Fix critical bugs: bd-169, bd-28, bd-393

- bd-169: Add -q/--quiet flag to bd init command
- bd-28: Improve error handling in RemoveDependency
  - Now checks RowsAffected and returns error if dependency doesn't exist
  - New removeDependencyIfExists() helper for collision remapping
- bd-393: CRITICAL - Fix auto-import skipping collisions
  - Auto-import was LOSING work from other workers
  - Now automatically remaps collisions to new IDs
  - Calls RemapCollisions() instead of skipping

All tests pass.

Amp-Thread-ID: https://ampcode.com/threads/T-cba86837-28db-47ce-94eb-67fade82376a
Co-authored-by: Amp <amp@ampcode.com>

internal/storage/sqlite/collision.go

@@ -466,11 +466,10 @@ func updateDependencyReferences(ctx context.Context, s *SQLiteStorage, idMapping
 
 	// Phase 2: Apply all collected changes
 	for _, update := range updates {
-		// Remove old dependency
-		if err := s.RemoveDependency(ctx, update.oldIssueID, update.oldDependsOnID, "import-remap"); err != nil {
-			// If the dependency doesn't exist (e.g., already removed), that's okay
-			// This can happen if both IssueID and DependsOnID were remapped
-			continue
+		// Remove old dependency - use RemoveDependencyIfExists which doesn't error on missing deps
+		if err := s.removeDependencyIfExists(ctx, update.oldIssueID, update.oldDependsOnID, "import-remap"); err != nil {
+			return fmt.Errorf("failed to remove old dependency %s -> %s: %w",
+				update.oldIssueID, update.oldDependsOnID, err)
 		}
 
 		// Add new dependency with updated IDs