✨ Add configurable RL pass timeouts

[flowerthrower]

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Description

Adds an opt-in timeout for individual RL compilation passes during training and inference.

pass_timeout is exposed through the existing entry points and remains disabled by default. Every compilation action receives the same user-provided value. A timeout truncates through the existing action-error path, and per-call settings are restored so singleton predictors do not leak timeout state.

The general watchdog uses POSIX real-time signals on the main thread. Qiskit's VF2 searches additionally run in an isolated worker with a hard deadline, and the same value is forwarded to Qiskit's and TKET's native search limits. Platforms or worker threads without POSIX signal support warn and continue without the general watchdog.

Reward policy is intentionally owned by the following reward PR.

This is position 7 of the stack. It depends on #797 and is followed by #799. No new package dependencies are introduced.

Part of #664

Checklist

• The pull request only contains commits that are focused and relevant to this change.
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[codecov]

Codecov Report

❌ Patch coverage is 84.40367% with 17 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/mqt/predictor/rl/predictorenv.py	77.7%	10 Missing ⚠️
src/mqt/predictor/rl/actions/qiskit_actions.py	88.5%	4 Missing ⚠️
src/mqt/predictor/rl/predictor.py	80.0%	3 Missing ⚠️

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