feat(ready): exclude pinned issues from bd ready (beads-92u)

Pinned issues are persistent anchors that should not appear in ready
work lists. This adds:

- Pinned bool field to Issue struct
- pinned INTEGER DEFAULT 0 column to schema
- Migration 023 to add pinned column to existing databases
- WHERE i.pinned = 0 filter in GetReadyWork query

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/storage/sqlite/queries.go

@@ -251,13 +251,15 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 
 	var contentHash sql.NullString
 	var compactedAtCommit sql.NullString
+	// Pinned field (bd-92u)
+	var pinned sql.NullInt64
 	err := s.db.QueryRowContext(ctx, `
 		SELECT id, content_hash, title, description, design, acceptance_criteria, notes,
 		       status, priority, issue_type, assignee, estimated_minutes,
 		       created_at, updated_at, closed_at, external_ref,
 		       compaction_level, compacted_at, compacted_at_commit, original_size, source_repo, close_reason,
 		       deleted_at, deleted_by, delete_reason, original_type,
-		       sender, ephemeral
+		       sender, ephemeral, pinned
 		FROM issues
 		WHERE id = ?
 	`, id).Scan(
@@ -267,7 +269,7 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 		&issue.CreatedAt, &issue.UpdatedAt, &closedAt, &externalRef,
 		&issue.CompactionLevel, &compactedAt, &compactedAtCommit, &originalSize, &sourceRepo, &closeReason,
 		&deletedAt, &deletedBy, &deleteReason, &originalType,
-		&sender, &ephemeral,
+		&sender, &ephemeral, &pinned,
 	)
 
 	if err == sql.ErrNoRows {
@@ -325,6 +327,10 @@ func (s *SQLiteStorage) GetIssue(ctx context.Context, id string) (*types.Issue,
 	if ephemeral.Valid && ephemeral.Int64 != 0 {
 		issue.Ephemeral = true
 	}
+	// Pinned field (bd-92u)
+	if pinned.Valid && pinned.Int64 != 0 {
+		issue.Pinned = true
+	}
 
 	// Fetch labels for this issue
 	labels, err := s.GetLabels(ctx, issue.ID)
@@ -431,6 +437,8 @@ func (s *SQLiteStorage) GetIssueByExternalRef(ctx context.Context, externalRef s
 	// Messaging fields (bd-kwro)
 	var sender sql.NullString
 	var ephemeral sql.NullInt64
+	// Pinned field (bd-92u)
+	var pinned sql.NullInt64
 
 	err := s.db.QueryRowContext(ctx, `
 		SELECT id, content_hash, title, description, design, acceptance_criteria, notes,
@@ -438,7 +446,7 @@ func (s *SQLiteStorage) GetIssueByExternalRef(ctx context.Context, externalRef s
 		       created_at, updated_at, closed_at, external_ref,
 		       compaction_level, compacted_at, compacted_at_commit, original_size, source_repo, close_reason,
 		       deleted_at, deleted_by, delete_reason, original_type,
-		       sender, ephemeral
+		       sender, ephemeral, pinned
 		FROM issues
 		WHERE external_ref = ?
 	`, externalRef).Scan(
@@ -448,7 +456,7 @@ func (s *SQLiteStorage) GetIssueByExternalRef(ctx context.Context, externalRef s
 		&issue.CreatedAt, &issue.UpdatedAt, &closedAt, &externalRefCol,
 		&issue.CompactionLevel, &compactedAt, &compactedAtCommit, &originalSize, &sourceRepo, &closeReason,
 		&deletedAt, &deletedBy, &deleteReason, &originalType,
-		&sender, &ephemeral,
+		&sender, &ephemeral, &pinned,
 	)
 
 	if err == sql.ErrNoRows {
@@ -506,6 +514,10 @@ func (s *SQLiteStorage) GetIssueByExternalRef(ctx context.Context, externalRef s
 	if ephemeral.Valid && ephemeral.Int64 != 0 {
 		issue.Ephemeral = true
 	}
+	// Pinned field (bd-92u)
+	if pinned.Valid && pinned.Int64 != 0 {
+		issue.Pinned = true
+	}
 
 	// Fetch labels for this issue
 	labels, err := s.GetLabels(ctx, issue.ID)
@@ -1564,7 +1576,7 @@ func (s *SQLiteStorage) SearchIssues(ctx context.Context, query string, filter t
 		       status, priority, issue_type, assignee, estimated_minutes,
 		       created_at, updated_at, closed_at, external_ref, source_repo, close_reason,
 		       deleted_at, deleted_by, delete_reason, original_type,
-		       sender, ephemeral
+		       sender, ephemeral, pinned
 		FROM issues
 		%s
 		ORDER BY priority ASC, created_at DESC