Fail migrations whose source or destination stops answering #14331

Tracks PR #14330.

Plan

Goal: Migrations whose source or destination accepts a connection but never answers should fail with a recorded error instead of sitting in processing forever (the cause of the intermittent Migrations E2E timeouts in CI).

What changes:

• src/Appwrite/Platform/Workers/Migrations.php: the scope-probe Client in authenticateSource() gets Target::CONNECT_TIMEOUT and Target::REQUEST_TIMEOUT.
• composer.json / composer.lock: utopia-php/migration points at branch fix/request-timeouts aliased as 2.0.9 (the library change is fix: time out stalled source and destination requests utopia-php/migration#232: 10s connect timeout, 30s no-bytes limit).
• tests/e2e/Services/Migrations/MigrationsBase.php: new testAppwriteMigrationFailsWhenSourceNeverAnswers, using a listening socket that never replies.

Remaining steps:

1. Merge and release fix: time out stalled source and destination requests utopia-php/migration#232.
2. Switch composer.json from the dev branch alias to the released tag and refresh composer.lock.

Done when:

• fix: time out stalled source and destination requests utopia-php/migration#232 is released
• PR fix: fail migrations whose source or destination stops answering #14330 depends on the tag, not the dev branch
• PR fix: fail migrations whose source or destination stops answering #14330 is merged with the new test and the Migrations E2E suite green