test(eventbus): pin WAMP prefix subscribe to details_arg='details'

[RameshHertzai]

Follow-up to the #118 review — the receive-path fix had no regression guard, and the "details=None → silent drop" class reintroduces easily.

What this adds

One unit test in tests/unit/test_eventbus_wamp_tts.py that pins EventBus.connect_wamp()'s subscription options. It captures the on_join handler registered via @component.on_join (with Component and the background thread mocked), drives it with a mock session, and asserts:

• session.subscribe(...) is called with a SubscribeOptions instance
• options.details_arg == 'details'
• options.match == 'prefix'

If the option is dropped or the plain-dict form ({'match': 'prefix'}) returns, autobahn never injects EventDetails, _on_wamp_event's details is None, and every inbound event hits if not wamp_topic: return — the test fails.

Verification

• New test: PASS
• Full file: 35 passed (no regression)

From the #118 review, not included here (with reasons)

• pytest not in sys.modules guard on the SelectorEventLoop policy block — the review flagged it as minor/harmless; adding it would skip setting the selector policy under pytest, which is a behavioral change with no upside for this test, so I left it out to keep the diff test-only.
• hevolveai HiveMind.connect_wamp sibling fix — that module is closed-source and loaded at runtime; its source isn't in this repo, so it can't be fixed here. Worth a separate task at that process's entry.

Scope: one test file, additive only.