## Context
Currently with the SQL Editor, the auto-completion via intellisense only
works nicely with the `.` operator - e.g after keying in a schema and
trying to find a table as such:
<img width="500" alt="image"
src="https://github.com/user-attachments/assets/86ec8455-47b9-43d3-925a-c13d0fd6ac44"
/>
But lacks support for finding the columns of a table after a `where`
clause - so the changes here addresses that by mainly adjust the
`PgSQLCompletionProvider`
Also addresses a number of type fixes (replaces all the `any` types)
<img width="500" alt="image"
src="https://github.com/user-attachments/assets/e23672a6-2b48-4a98-b300-69f822d12b38"
/>
<img width="415" height="319" alt="image"
src="https://github.com/user-attachments/assets/e6ee64d2-90dd-47d6-9fd2-e8b07821ebb6"
/>
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Improved PostgreSQL SQL editor suggestions with table, column, alias,
schema, and join-aware completions.
* Added context-aware support for statements, quoted identifiers,
subqueries, and qualified columns.
* Enhanced PostgreSQL function signature assistance.
* Added safer behavior when database metadata is incomplete or
unavailable.
* **Bug Fixes**
* Prioritized relevant columns and removed duplicate suggestions.
* **Tests**
* Added comprehensive coverage for SQL parsing, metadata handling, and
completion behavior.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
## Context
Adds an intellisense toggle for explorer notebooks similar to SQL editor
+ have QueryEditor render definitions via `useAddDefinition`
<img width="259" height="162" alt="image"
src="https://github.com/user-attachments/assets/278fdabd-1a24-4769-972e-1bce29060463"
/>
So intellisense will be running in the QueryEditor if intellisense is
enabled + source selected is database, otherwise will not run.
<img width="982" height="411" alt="image"
src="https://github.com/user-attachments/assets/19497aa0-36fc-49ab-853d-cb938b5b18e7"
/>
Also updated `useAddDefinition` logic to flush the table columns +
functions cache in react query
- For context in the past we had users run into browser performance
issues when definitions were loaded if their database is really big
- Hence why we originally added this intellisense toggle
- But we previously also required users to refresh the browser after
disabling intellisense, as a manual way to flush the cache
- So this change should remove the need to refresh the browser after
disabling intellisense
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Added PostgreSQL IntelliSense with definitions, formatting, and code
completions in SQL editors.
* Added a notebook option to enable or disable IntelliSense, with the
preference saved between sessions.
* Improved the notebook’s empty-state appearance.
* **Bug Fixes**
* Improved IntelliSense cleanup and prevented duplicate registrations
when disabled.
* Improved query execution state handling while background IntelliSense
data loads.
* **Tests**
* Added coverage for shared registration, cleanup, preference
persistence, and IntelliSense-related query handling.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Joshen Lim