chore(studio): switch to type: module and convert configs to ESM/TS (#44839)

Switch studio's package.json to `"type": "module"` so the package runs
as native ESM. This aligns the runtime module system with what we
actually write (`import`/`export`), improves tree-shaking, and reduces
friction with ESM-only dependencies.

**Changed:**
- `next.config.js` → `next.config.ts` – ESM imports/exports, proper TS
types, fixed type narrowing on redirect `has` and `basePath` fields
- `csp.js` → `csp.ts` – `module.exports.getCSP` → named `export
function`
- `tailwind.config.js` → `tailwind.config.ts` – ESM imports
- `postcss.config.js` – `module.exports` → `export default` (stays `.js`
since PostCSS doesn't support TS configs)

**Removed:**
- Unused `path` import in next config
- Deprecated Sentry `hideSourceMaps` option (default behavior in Sentry
v10)

**Added:**
- Type declaration for `config/tailwind.config` CJS package

## To test

- A general smoke test of studio should suffice

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
* Modernized the Studio package to ES module style and improved
TypeScript typings and config declarations to reduce build/runtime
issues.
* Updated styling and post-processing configuration format for more
consistent tooling behavior.

* **Chores**
* Updated code ownership entries to reflect migrated/renamed
configuration files.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Alaister Young <10985857+alaister@users.noreply.github.com>

.github/CODEOWNERS

@@ -14,7 +14,7 @@
 
 /docker/ @supabase/cli @supabase/self-hosted
 
-/apps/studio/csp.js                                                 @supabase/security
+/apps/studio/csp.ts                                                 @supabase/security
 /apps/studio/components/interfaces/Billing/Payment                  @supabase/security
 /apps/studio/components/interfaces/Organization/Documents/          @supabase/security
 /apps/studio/pages/new/index.tsx                                    @supabase/security