perf(pipeline): parallel prefetch and lean revision GET

GetRevisionSummary без preview_fragments; boundedRepoCtx для GetRevision;
parallel CDN prefetch с ctx из ingest.

Co-authored-by: Cursor <[email protected]>

internal/repository/ctx.go

@@ -0,0 +1,19 @@
+package repository
+
+import (
+	"context"
+	"time"
+)
+
+const defaultRepoTimeout = 60 * time.Second
+
+// boundedRepoCtx returns a context with default repository I/O timeout.
+func boundedRepoCtx(parent context.Context) (context.Context, context.CancelFunc) {
+	if parent == nil {
+		parent = context.Background()
+	}
+	if _, ok := parent.Deadline(); ok {
+		return parent, func() {}
+	}
+	return context.WithTimeout(parent, defaultRepoTimeout)
+}

internal/repository/postgres.go

@@ -659,7 +659,8 @@ func (p *Postgres) DeleteSpeaker(tenantID, id string) error {
 }
 
 func (p *Postgres) GetRevision(tenantID, revisionID string) (*store.Revision, error) {
-	ctx := context.Background()
+	ctx, cancel := boundedRepoCtx(context.Background())
+	defer cancel()
 	var r store.Revision
 	var mod *string
 	var parent *string
@@ -691,6 +692,33 @@ func (p *Postgres) GetRevision(tenantID, revisionID string) (*store.Revision, er
 	return &r, nil
 }
 
+func (p *Postgres) GetRevisionSummary(tenantID, revisionID string) (*store.Revision, error) {
+	ctx, cancel := boundedRepoCtx(context.Background())
+	defer cancel()
+	var r store.Revision
+	var mod *string
+	var parent *string
+	var prefixCount int
+	err := p.pool.QueryRow(ctx, `
+		SELECT id::text, tenant_id::text, module_id::text, content_hash, parent_revision_id::text,
+			COALESCE((meta_json->>'materialized_prefix_count')::int, 0), created_at
+		FROM config_revision WHERE id=$1 AND tenant_id=$2`, revisionID, tenantID).Scan(
+		&r.ID, &r.TenantID, &mod, &r.ContentHash, &parent, &prefixCount, &r.CreatedAt)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, store.ErrNotFound
+		}
+		return nil, err
+	}
+	if mod != nil {
+		r.ModuleID = *mod
+	}
+	r.ParentRevisionID = strOrNil(parent)
+	r.MaterializedPrefixCount = prefixCount
+	r.PreviewFragments = map[string]string{}
+	return &r, nil
+}
+
 func (p *Postgres) ListRevisions(tenantID, moduleID string, cursor string, limit int) ([]*store.Revision, string, bool) {
 	if limit <= 0 {
 		limit = 50