feat(sidebar): show schemas as collapsible sections in the Tables sidebar

[luizvergennes]

solves #1296

Adds a Sidebar group in the settings, with a "Display schemas on the sidebar" option:

Enabling this option, shows all schemas on the sidebar, and they can be expanded:

✨ Used AI to help me create this PR.

[github-actions]

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[luizvergennes]

I have read the CLA Document and I hereby sign the CLA.

[luizvergennes]

I do feel it could still be expanded a bit, to allow the tabs to also work across, schemas. I did not test, on my build. But on the production app, the tabs close as soon as I switch to another schema.

[datlechin]

Thank you. The PR looks good, but it needs some improvement. I’ll continue to improve it.

[datlechin]

Found one more bug while testing the branch: clicking a table in a non-current schema (e.g. `auth.audit_log_entries` while connected to `public`) errored with `relation "audit_log_entries" does not exist` because the SELECT was unqualified.

Root cause: `onDoubleClick` → `openTableTab(tableName)` only passed the table name, never the schema. `tableContext.schemaName` was being set to the connection's current schema, and the SELECT was built without the schema prefix. The PR's earlier attempt to fix this by calling `switchSchema` before opening was brittle (mutates connection-wide state, races with other tabs, fails silently for drivers without `SchemaSwitchable`).

Deeply correct fix in 12b20b8 on `pr-1300-review-fixes`:

• `openTableTab` gains a `schema: String?` parameter
• Threads schema through `addTableTab` / `addPreviewTableTab` / `buildBaseTableQuery` (the SQL builder already supported it)
• Sidebar callback passes `table.schema` directly
• Fast-path tab match now compares schema too (so opening `auth.users` and `public.users` correctly creates separate tabs instead of reusing)
• `handleTableOpen` schema-switch hack removed entirely - it's now just `onDoubleClick?(table)`

Result: SELECT is built as `SELECT * FROM "auth"."audit_log_entries" LIMIT 1000` regardless of which schema the connection is currently pointed at. No connection-state mutation, no schema thrashing across windows.

[luizvergennes]

Merged your fix into mine! Thank you so much for your help/work! 🙌