Wire HotplugMonitor into Server, or delete it — v1.0 reliability primitive is fiction

[stanvx]

Parent

Architecture review (2026-06-21). Slice 3 of 6 from the deepening series. Documented at server/usbip-server/src/hotplug.rs:40-106 and CONTEXT.md:35-37.

What to build

HotplugSource, HotplugEvent, and HotplugMonitor are declared, exported, and tested — but no Server ever instantiates one. CONTEXT.md lists hot-plug detection as a v1.0 reliability primitive. The agent must pick one of two paths and execute end-to-end:

Path A — wire it. Server::new constructs a HotplugMonitor::new(rusb::Context::new()?) and spawns a task that subscribes to attach/detach events. Detach events close active client sessions with a structured error. Attach events refresh the advertised device list and re-broadcast over mDNS. Tests must include a fake libusb context producing a scripted attach/detach sequence.

Path B — delete it. Remove hotplug.rs, remove the tests/hotplug_integration.rs file, remove the symbols from lib.rs re-exports, and amend CONTEXT.md to demote hot-plug detection to "deferred to v1.1". Update any callers (ARCHITECTURE.md, CLAUDE.md) that reference it.

The choice belongs to the agent; the discipline is that one of the two lands, not both, not neither.

Acceptance criteria

• Exactly one of: (a) Server constructs a HotplugMonitor and the integration test runs end-to-end, or (b) hotplug.rs and its tests are deleted and CONTEXT.md is amended
• If Path A: detach events close active client sessions with a structured error carrying the device's VID:PID and correlation_id
• If Path A: grep -r 'HotplugMonitor::new' server/usbip-server/src/ returns at least one construction site
• If Path B: grep -r 'hotplug\|Hotplug' server/usbip-server/src/ returns zero matches and tests/hotplug_integration.rs no longer exists
• CONTEXT.md v1.0 contract section matches the chosen path (no fiction either way)
• cargo test -p usbip-server --release passes; cargo clippy --workspace -- -D warnings clean

Blocked by

• Reconcile docs to code — name module ownership in CONTEXT.md, fix 12+ divergences #27 (Reconcile docs to code) — needs the HotplugOwner line in CONTEXT.md before the wire path can claim "the one place that owns hot-plug"