feat: CGEvent tap diagnostics — conflict detection + live event monitor

[AprilNEA]

Adds an in-app way to answer "is another app intercepting my mouse / what's in the CGEvent stream?" — the productized version of hand-running CGGetEventTapList.

What's in it

• openlogi-hook: Hook::list_event_taps() enumerates every event tap in the login session (owner, location, active/listen, enabled) via a hand-bound CGGetEventTapList + proc_pidpath (read-only, no Accessibility needed). EventTapInfo::gates_input() / known_input_conflict() classify the lag-relevant ones against a curated driver list (Logi Options+, SteerMouse, BetterMouse, Mac Mouse Fix, LinearMouse, …). A list_taps example doubles as a headless diagnostic. Latency fields are dropped (uninitialised sentinel values).
• agent (protocol v4): an opt-in live event monitor. A shared EventMonitor buffers button/scroll/interrupt events (pointer moves excluded); the freeze-sensitive hook callback pays only one relaxed atomic load while monitoring is off. New poll_event_monitor IPC method drains + implicitly enables it; an idle janitor disables it once the GUI stops polling. Bumps PROTOCOL_VERSION 3→4 and regenerates the wire goldens (agent + GUI ship together).
• GUI: a macOS Diagnostics settings page. Release surfaces the curated conflict warning; debug builds also show the full tap list and the live monitor (polls the agent while the window is open). Five new strings translated into all 20 locales.

Verification

• list_event_taps() output matches a reference Swift CGGetEventTapList dump byte-for-byte.
• Unit tests (classification, monitor buffer) + regenerated wire goldens pass; GUI compiles/links, clippy-clean under -D warnings, i18n parity holds.
• Diagnostics page rendered and visually confirmed (layout uses Axis::Vertical so the wide content wraps full-width).

Notes

• Debug-only tap-list / live-monitor strings are intentionally left English (developer diagnostics).
• Touches the same 20 locale files as i18n: localize the About window update section + Crowdin sync #275 — whichever merges second needs a trivial rebase (both only append keys).

[greptile-apps]

Greptile Summary

This PR adds an in-app CGEvent tap diagnostics feature: Hook::list_event_taps() enumerates active taps via hand-bound CGGetEventTapList + proc_pidpath, a curated conflict list flags known competing input drivers, and an opt-in live event monitor (agent-side EventMonitor + poll_event_monitor IPC) feeds a debug panel in Settings. All three previously reported issues — Relaxed atomic ordering in poll/janitor, per-render CGGetEventTapList syscall storm, and the janitor's immediate first tick on agent restart — have been correctly addressed in the current commit.

• event_monitor.rs: The Release/Acquire pairing on enabled is correct; interval_at delays the first janitor tick by a full IDLE_TICK to survive agent restarts.
• macos.rs: The hand-declared CGEventTapInformation repr(C) struct reproduces the correct 48-byte Apple layout including the 4-byte padding before events_of_interest; process_name gracefully handles process exits.
• Protocol: version bumped 8→9 with MonitorEvent variants marked append-only and wire goldens regenerated.

Confidence Score: 5/5

Safe to merge: adds a read-only diagnostic path with no new writes beyond a bounded VecDeque, and the hook hot path pays only one relaxed atomic load while monitoring is off.

All three concurrency issues from prior review rounds are correctly fixed. The repr(C) layout matches Apple's 48-byte stride. No correctness, data-safety, or security issues remain.

No files require special attention.

Important Files Changed

Filename	Overview
crates/openlogi-agent-core/src/event_monitor.rs	New EventMonitor with correct Release/Acquire pairing on enabled, interval_at for delayed first janitor tick, and bounded VecDeque buffer — previous thread concerns fully addressed.
crates/openlogi-hook/src/macos.rs	Hand-bound CGGetEventTapList + proc_pidpath with correct repr(C) layout matching Apple's 48-byte CGEventTapInformation stride (including u64 alignment padding).
crates/openlogi-hook/src/lib.rs	Adds EventTapInfo, TapLocation, gates_input(), known_input_conflict() with curated list; clean logic and well-covered by new unit tests.
crates/openlogi-agent-core/src/ipc.rs	PROTOCOL_VERSION bumped 8→9 with MonitorEvent variants append-only; wire golden regenerated correctly.
crates/openlogi-gui/src/windows/settings.rs	Monitor task correctly held in _monitor_task (drop-to-stop), taps cached in AppState to avoid per-frame syscalls; refresh_windows() fires unconditionally every 300ms.
crates/openlogi-gui/src/windows/settings/diagnostics.rs	Diagnostics page correctly splits debug (cached taps) vs release (live taps) code paths; conflict dedup and format_monitor_event are straightforward.
crates/openlogi-agent-core/src/hook_runtime.rs	monitor.record() injected before the match dispatch; single relaxed atomic load on the hot path when monitoring is off.
crates/openlogi-gui/src/ipc_client.rs	PollEventMonitor command gated on cfg(all(target_os = macos, debug_assertions)); reply channel error ignored correctly with let _.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant GUI as GUI (debug)
    participant IPC as IPC Client
    participant Agent as AgentServer
    participant EM as EventMonitor
    participant Hook as Hook Callback
    participant Janitor as Idle Janitor

    Note over GUI: Settings window opens
    GUI->>IPC: PollEventMonitor(tx) every 300ms
    IPC->>Agent: poll_event_monitor RPC
    Agent->>EM: poll()
    Note over EM: polled.store(true,Relaxed) then enabled.store(true,Release)
    EM-->>Agent: Vec MonitorEvent
    Agent-->>IPC: Vec MonitorEvent
    IPC-->>GUI: reply via oneshot rx

    Hook->>EM: record(event)
    Note over EM: enabled.load(Relaxed) fast path

    Note over Janitor: every 3s via interval_at
    Janitor->>EM: enabled.load(Acquire)
    Note over EM: if enabled and not polled: disable()

    Note over GUI: Settings window closes
    Note over GUI: _monitor_task dropped, loop cancelled
    Note over Janitor: next tick disables monitoring

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sequenceDiagram
    participant GUI as GUI (debug)
    participant IPC as IPC Client
    participant Agent as AgentServer
    participant EM as EventMonitor
    participant Hook as Hook Callback
    participant Janitor as Idle Janitor

    Note over GUI: Settings window opens
    GUI->>IPC: PollEventMonitor(tx) every 300ms
    IPC->>Agent: poll_event_monitor RPC
    Agent->>EM: poll()
    Note over EM: polled.store(true,Relaxed) then enabled.store(true,Release)
    EM-->>Agent: Vec MonitorEvent
    Agent-->>IPC: Vec MonitorEvent
    IPC-->>GUI: reply via oneshot rx

    Hook->>EM: record(event)
    Note over EM: enabled.load(Relaxed) fast path

    Note over Janitor: every 3s via interval_at
    Janitor->>EM: enabled.load(Acquire)
    Note over EM: if enabled and not polled: disable()

    Note over GUI: Settings window closes
    Note over GUI: _monitor_task dropped, loop cancelled
    Note over Janitor: next tick disables monitoring

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_{Reviews (3): Last reviewed commit: "perf(gui): cache the diagnostics event-t..." | Re-trigger Greptile}