TIA: runs without --tia write to the machine-global TIA state

addOutput() (src/Plugins/Tia.php:661) has no check for whether TIA is enabled. Its only write-suppressor is $writesSuppressed, which is set for mutation-testing runs only:

// src/Plugins/Tia.php:491-493
if (getenv(self::ENV_MUTATION_TESTING) !== false) {
    $this->writesSuppressed = true;
}

So a plain pest run — no --tia — reaches snapshotTestResults() at :692 and writes into ~/.pest/tia/<key>/.

Observed: a plain non-TIA run wrote 2,025 → 2,027 results into machine-global TIA state, in a run that never requested TIA.

Effects: state accumulates for users who never opted in, and a run cannot be told from its own behaviour whether it is contributing to TIA's state.

Fix: return early from addOutput() when TIA was not requested.

v5.1.0.

Start in src/Plugins/Tia.php at addOutput() around line 661, then read how TIA request state is tracked before snapshotTestResults() at line 692. Add the requested-state guard described in the issue and verify that a plain pest run does not write to ~/.pest/tia// while TIA runs still record results.