fix: Validate the wait_for_action_attempt option

[razor-x]

What

wait_for_action_attempt was dispatched with an is True identity check, so any truthy non-True value — 1, "true" (an env string), a numpy bool — silently fell through to no waiting and no failure raising: the caller got back a pending attempt and believed the door unlocked (SDK audit finding M2). Dict options were equally silent: unknown keys were ignored, so the docstring's own poll_interval typo polled at the default rate without complaint.

This PR makes the option strict, in both sync and async variants:

• A new validate_wait_for_action_attempt raises SeamInvalidOptionsError for anything that is not a bool or an options dict, for unknown dict keys (naming the key — this makes the poll_interval typo fail loudly), and for non-numeric dict values.
• Constructor None now means "use the default" (wait), matching what per-request None already meant. Previously Seam(wait_for_action_attempt=None) silently behaved as False while per-request None meant "use the client default" — the same annotation with opposite meanings. ⚠️ Behavior change for anyone passing None explicitly to disable waiting; pass False for that.
• The documented-but-dead seam.wait_for_action_attempt instance attribute is now a real property backed by defaults, on all four clients (Seam, AsyncSeam, SeamWithoutWorkspace, AsyncSeamWithoutWorkspace). It previously did nothing after construction — routes read defaults, which the attribute never touched. Reading it reflects the live default; assigning it validates and takes effect. SeamWithoutWorkspace also gains the same public defaults dict the other clients had.
• Fixed the 'poll_interval' → 'polling_interval' typo in ten constructor/factory docstrings (the code always read polling_interval; the README was already correct).

Depends on #636 (stacked; diff shrinks once it merges).

Testing

New test/wait_for_action_attempt_option_test.py (sync + async): junk values raise at construction, at route call, and at property assignment with pinned messages; unknown dict key and non-numeric value raise naming the problem; constructor None waits; the property reflects and updates route behavior.

Revert check: with the source reverted, the junk-value test fails with DID NOT RAISE (the silent-pending audit symptom) and the ctor-None test shows defaults holding None (behaving as False).

Full suite: 203 passed; mypy, pylint (10.00), black clean.

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https://claude.ai/code/session_01Y1RzepycXEYA3LStfjt8cY

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