feat(scripting): add MongoDB support to JavaScript scripting

[oesukam]

Extends JS scripting mode to MongoDB connections (previously SQL-only).

How it works

In a Mongo script, db.query(...) takes a mongo-shell command string (db.coll.find({…})) instead of SQL. The Mongo driver's stream() already parses that syntax and streams documents as rows, so the existing ScriptRunner seam works unchanged — only the run_script SQL-only gate needed relaxing to also allow QueryLang::MongoShell.

const active = await db.query('db.users.find({ active: true })');
for (const u of active) console.log(u.name);
return active;

The array result, console strip, ⌘+Enter, and return-value echo all behave exactly as they do for SQL scripting.

Changes

• Backend: run_script accepts SQL or MongoShell connections.
• Frontend: scriptingAvailable includes the mongo engine; the JS-in-SQL guard is skipped for Mongo (a shell command isn't a mis-typed script).
• Test: real-driver integration test runs db.query('db.users.find({…})') through the actual Mongo driver (testcontainer) in a script and iterates the array result.
• Docs: scripting page now covers MongoDB + the Console strip.

Tests

Mongo real-driver script test passes; fmt/clippy clean; frontend tsc + lint (0 errors) + 276 unit tests green.

Completes the MongoDB scripting task from the scripting-mode roadmap.