Fix Windows capture paths and public WebSocket text subscriptions

[PureSaber]

Capture failed when Windows extended-length drive paths reached the physical-volume probe, and public subscription JSON was sent as a binary WebSocket frame. Normalize only the volume-device anchor while retaining extended file paths, and send subscription JSON as UTF-8 text. UNC/device paths and OS-denied probes still fail closed.

Validation: 863 tests passed, 2 skipped; Ruff lint/format and pip check passed. All tracked branch coverage is 83.13% (80% gate), every core module clears its 90% gate. A real local WebSocket round trip verifies text frames; Windows anchor tests cover both accepted spellings and rejected non-drive paths. No issue is required for these acceptance-driven fixes; no market data or credentials are included.

[PureSaber]

Reviewed the changed storage and transport paths at this head. Extended local-drive paths resolve only the device anchor; unsupported Windows anchors still reject before probing. Subscription payloads remain byte-compatible at the internal interface while a real local WebSocket verifies a UTF-8 text frame on the wire. Full local tests/coverage and lint/format/pip check passed. No blocking finding remains from this review. This is the implementing agent's review, not an independent human approval; CI is checked separately before merge.