[J2TeamNNL]

Summary

• New Database > Table Health tab, one per connection. Enabled only for PostgreSQL, MySQL and MariaDB, and dimmed in Agent mode.
• Reports on the database selected in the sidebar, captured when a refresh starts. The model owns the read, so a pane switch neither drops the first load nor strands it. Every read runs in one withMetadataDriver(scope:) lease on a pooled connection, never the user's session, so a failing check cannot abort an open transaction. No database selected asks for one.
• PostgreSQL (every schema): bloated tables, unused indexes, tables without a primary key, foreign keys without an index.
  • Unused skips unique, constraint and foreign key indexes, partition indexes a parent owns, materialized views and other sessions' pg_temp schemas.
  • A partitioned table is listed once; its foreign key fix is CREATE INDEX, since PostgreSQL refuses CONCURRENTLY there.
  • track_counts = off skips the bloat and unused checks and says why.
• MySQL and MariaDB: unused indexes, redundant indexes, tables without a primary key.
  • Unused skips unique and full-text indexes (MATCH reads are not counted), an index that leads with a foreign key's columns on either end, from any database (InnoDB reads it uncounted and refuses to drop it, error 1553), and a table with no counted I/O, which is how a table setup_objects leaves out looks.
  • Skipped, with the reason, when performance_schema is off, the wait/io/table/sql/handler instrument or global_instrumentation consumer is disabled, or the database has no counted table I/O.
  • Redundant never names an index covered only by an invisible (MySQL) or ignored (MariaDB) one, and never a full-text index, whose parser STATISTICS does not show. Index rows group by exact name and key position, so case-distinct tables cannot split an index.
• Each finding previews its fix, quoted by the driver, in the themed SQLStatementPreview. Nothing runs it: Open in Editor, Copy, Open Table.
• No cap on findings.
• Refresh (Cmd+R and the toolbar) now reloads Table Health, Server Dashboard, Query Insights, Users & Roles and object source tabs. It did nothing on those tabs. One AppEvents.tabRefreshRequested replaces versionHistoryRefreshRequested and tableListingRefreshRequested.
• One showSingletonTab(_:) and QueryTabManager.addSingletonTab(_:) replace the four Server Dashboard, Users & Roles, Query Insights and Table Health copies.
• PaneRefreshControls is shared by Query Insights and Table Health. VoiceOver now reads the last update time.
• New tab kind tableHealth: AppleScript table health (TPkx), MCP snapshot tableHealth.
• Docs: docs(features): add the Table Health page docs#147.

Screenshots

Test plan

• PostgreSQLTableHealthProviderTests, MySQLTableHealthProviderTests: parsing, fix SQL, partitioned fix, skipped checks, foreign key and invisible index rules, one failing check isolated, index catalog read once.
• TableHealthViewModelTests: one lease on the browse scope with .bulk, a pane switch during the first load, no database, offline then online, failed check keeps findings, selection.
• MainContentCoordinatorRefreshTests: Refresh reaches each self-loading tab and Users & Roles. MainMenuBuilderTests: engine gate and Agent mode.
• apple/scripts/probes/check-table-health-catalogs.sh runs every query and fix against real servers: PASS on PostgreSQL 12.22 and 17.11, MySQL 8.4.13, MariaDB 10.5.29 and 11.8.9.

Fixes #3935