Store self-metrics sweep fails on TimescaleDB 2.29+ (catalog chunk.schema_name/table_name removed); breaks the store-log sweep and collector-cost flush too; live today on the Linux compose image #3918

Found by the adversarial review of #3908 (TimescaleDB 2.28.1 → 2.30.1) and verified against real stores.

TimescaleDB 2.29.0 dropped _timescaledb_catalog.chunk.schema_name / table_name. The update script says "add chunk.relid and drop … schema_name, table_name". StoreSelfMetrics.TimescaleInventoriedPredicateSql (Darling/PerformanceMonitor.Darling.Storage/StoreSelfMetrics.cs ~682) joins on those columns. Running the production StoreSelfMetrics.SweepAsync:

• 2.28.1: OK, 248 rows.
• 2.30.1, upgraded and fresh alike: 42703: column ch.schema_name does not exist.

Impact:

• The hourly store self-metrics sweep fails. Because it shares a try block in DarlingWorker (~6729-6765), the store-log sweep (The store's own PostgreSQL log is invisible to the product — collect it as a self-monitoring source #3021) and the collector-cost flush (Self-monitor collector cost: per-collector sql_ms/rows metric, panel, and regression alert #2674) stop with it.
• The MCP get_store_metrics read fails too (DarlingStoreMetricsReader).

This is broken today for Linux compose users, not only after a bundle bump. Darling/compose/docker-compose.yml uses timescale/timescaledb:latest-pg17, which is the same image as 2.30.1-pg17. It also blocks #3908: darling-pg CI goes red on a 2.30.1 runtime (StoreSelfMetricsTests runs SweepAsync live).

Fix constraints:

• It must work on 2.28.1 (the current bundle, stores degraded after a failed update, bring-your-own) and on 2.29+.
• On 2.29+, compressed data is no longer a chunk catalog row. Its relations must still be excluded from the catch-all rows (for example via _timescaledb_catalog.compression_settings.compress_relid), or they are counted twice: hypertable_detailed_size already includes them. On 2.30.1, 843,776 = 24,576 root + 819,200 chunk and compressed bytes.
• A unit test pins the literal SQL (StoreSelfMetricsTests.cs ~348).