#26359 fix(ws): allow ws.once() to work multiple times

Summary

• Fixes ws.once() only working on the first call for each event type
• The bug was in the #onOrOnce method which tracked native listeners via a bitset but didn't account for once listeners auto-removing after firing
• Now only persistent on() listeners set the bitset; once() listeners always add new native handlers unless a persistent listener already exists

Test plan

• Added regression test test/regression/issue/26358.test.ts
• Test verifies once('message') works multiple times
• Test verifies once('pong') works multiple times
• Test verifies on() still works correctly
• Test verifies mixing on() and once() works correctly
• Verified test fails with USE_SYSTEM_BUN=1 (bug exists)
• Verified test passes with bun bd test (fix works)

Fixes #26358

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