feat(revisions): add pruning estimate and cleanup endpoints

Implemented new endpoints for estimating and pruning revisions, including detailed schemas for requests and responses. The `RevisionPruneEstimate` and `RevisionPruneResult` components were added to the OpenAPI documentation, enhancing the API's functionality for managing revision retention. Updated the backend to support these operations and integrated them into the tenant settings UI for improved user interaction.

internal/repository/postgres.go

@@ -970,43 +970,6 @@ func (p *Postgres) RevisionDiff(tenantID, aID, bID string) (map[string]any, erro
 	}, nil
 }
 
-func (p *Postgres) PruneRevisionsBefore(tenantID string, cutoff time.Time) (int, error) {
-	ctx := context.Background()
-	total := 0
-	const batchSize = 50
-	for {
-		cmd, err := p.pool.Exec(ctx, `
-			DELETE FROM config_revision AS cr
-			WHERE cr.id IN (
-				SELECT id FROM config_revision
-				WHERE tenant_id = $1
-				  AND created_at < $2
-				  AND id <> (
-					SELECT id FROM config_revision
-					WHERE tenant_id = $1
-					ORDER BY created_at DESC
-					LIMIT 1
-				  )
-				  AND NOT EXISTS (
-					SELECT 1 FROM bgp_speaker AS sp
-					WHERE sp.tenant_id = $1
-					  AND (sp.last_applied_revision_id = config_revision.id OR sp.published_revision_id = config_revision.id)
-				  )
-				ORDER BY created_at ASC
-				LIMIT $3
-			)`, tenantID, cutoff.UTC(), batchSize)
-		if err != nil {
-			return total, err
-		}
-		n := int(cmd.RowsAffected())
-		total += n
-		if n < batchSize {
-			break
-		}
-	}
-	return total, nil
-}
-
 func (p *Postgres) SetLastAppliedRevision(tenantID, speakerID, revisionID string) error {
 	ctx := context.Background()
 	tag, err := p.pool.Exec(ctx, `