Hide cursor overlay while user is typing

[Catafal]

Feature

Hide Clicky cursor when user types, matching macOS native behavior (resolves #37)

Problem

When macOS hides the system cursor on keypress (NSCursor.setHiddenUntilMouseMoves(true)), the Clicky blue cursor companion kept rendering at full opacity — floating mid-screen while the system cursor was invisible. Every user who types sees this visual mismatch.

Root Cause

No typing-detection existed anywhere in the codebase. The CGEvent tap in GlobalPushToTalkShortcutMonitor already received every .keyDown event system-wide (it was already in the event mask), but silently dropped all non-PTT keystrokes.

Solution

Extend the existing event tap — no new taps, no new permissions needed.

GlobalPushToTalkShortcutMonitor.swift

• New @Published var isUserTyping: Bool
• In handleGlobalEventTap: set isUserTyping = true when eventType == .keyDown && shortcutTransition == .none (PTT combo uses .flagsChanged, never hits this path)

CompanionManager.swift

• Forwards isUserTyping via Combine subscription
• Exposes resetUserTyping() for BlueCursorView to call on mouse move

OverlayWindow.swift

• New shouldHideForTyping computed property: isUserTyping && voiceState == .idle
• Triangle opacity gate: && !shouldHideForTyping added
• 16ms cursor-tracking timer: detects mouse movement >1pt and calls resetUserTyping() — mirrors the "until mouse moves" part of setHiddenUntilMouseMoves

Behavior

Scenario	Before	After
User types while cursor is visible (idle)	Cursor stays visible	Cursor hides
User moves mouse after typing	Cursor stays hidden	Cursor reappears
User presses PTT (ctrl+option)	Voice activates	Voice activates, cursor not hidden
Voice active (.listening/.processing/.responding)	Waveform/spinner show	Waveform/spinner stay visible

Testing

• GIVEN Clicky cursor visible + voiceState idle, WHEN any key pressed, THEN cursor hides ✓
• GIVEN cursor hidden by typing, WHEN mouse moves, THEN cursor reappears ✓
• GIVEN user presses ctrl+option (PTT), THEN voice activates normally, no hide ✓
• GIVEN voice active, WHEN user types, THEN waveform/spinner remain visible ✓

Closes #37