feat(web): add SQL autocomplete

[omercnet]

Summary

• add CodeMirror SQL schema reconfiguration for table/field autocomplete
• wire loaded table metadata into the SQL tab and fetch fields only when SQL tab is active
• document autocomplete in README and docs site

Verification

• npm run build
• npm test
• npm run coverage
• node --check web/sql-tab.js web/app.js web/vendor/src/codemirror6.entry.js web/app.test.js

---

Summary by cubic

Add schema‑aware SQL autocomplete to the SQL tab that suggests tables and columns from your query’s relations. Columns load only when the SQL tab is active to keep things fast.

• New Features

  • Table and relation‑aware column autocomplete in the CodeMirror SQL editor.
  • Columns are fetched lazily when the SQL tab is active; textarea mode skips fetches.
  • Resilient fetching: ignores stale responses on DB switch and swallows errors; default schema is "public" or the first available.
  • New editor API setSQLConfig; app passes tables into SqlTab; README and docs updated.

• Bug Fixes

  • Column completion now sources only from relations in the current query and doesn’t override table suggestions while typing.
  • Avoids bare column completions when duplicate table names exist across schemas.
  • Autocomplete popup is themed to match the app.

^{Written for commit 4d6f9fa. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 6 files

_{Re-trigger cubic}

[cubic-dev-ai]

1 issue found across 5 files (changes from recent commits).

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>