fix(litestar): register plugin middleware at the outer boundary

[CyberneticX-Tech]

Description

SQLSpecPlugin.on_app_init appended its middleware to app_config.middleware:

app_config.middleware = [*(app_config.middleware or []), *new_middlewares]

Litestar runs middleware outermost first, so appending makes the plugin's entries the innermost in the pipeline. Any user middleware that rejects a request early (auth, CORS, rate limiting) short-circuits before the correlation middleware ever runs, and the access log and error hooks for exactly the requests you most want to trace have no correlation ID.

Fix

Prepend instead, so the correlation context is established at the outer boundary:

app_config.middleware = [*new_middlewares, *(app_config.middleware or [])]

Verification

Reproduced with a small app: a user middleware that returns 401 before the handler, with X-Request-ID: abc-123 on the request.

Before:

status: 401
correlation seen by outer rejecting middleware: None

After:

status: 401
correlation seen by outer rejecting middleware: 'abc-123'

Tests

Added test_correlation_middleware_runs_before_user_middleware to the existing correlation middleware tests. It installs a middleware that rejects with 401, then asserts the correlation ID was populated at that point.

Confirmed it is a real regression test. With the fix reverted:

FAIL test_correlation_middleware_runs_before_user_middleware: AssertionError
6 passed, 1 failed

and with the fix restored all 7 pass. ruff check and ruff format --check pass on both touched files.

Closes #729