Fix release E2E notification and keyboard flakes

[nwparker]

Summary

• keep inactive-worktree agent-complete notifications dispatchable when the live PTY is still identifiable through the pane key
• add unit coverage for pane-key PTY liveness fallback versus stale notifications
• make the Russian-layout kitty keyboard E2E target the active pane and emit the Chromium Linux input text path

Verification

• pnpm run lint
• pnpm run tc
• pnpm exec vitest run --config config/vitest.config.ts src/renderer/src/components/terminal-pane/use-notification-dispatch.test.ts src/renderer/src/hooks/agent-hook-completion-notifications.test.ts src/renderer/src/components/terminal-pane/agent-completion-coordinator.test.ts src/renderer/src/components/terminal-pane/xterm-bypass-policy.test.ts
• pnpm exec electron-vite build --mode e2e
• CI=true SKIP_BUILD=1 pnpm exec playwright test --config tests/playwright.config.ts --project=electron-headless --repeat-each=5 tests/e2e/droid-notification.spec.ts tests/e2e/terminal-shortcuts.spec.ts

Fixes the release E2E failures from https://github.com/stablyai/orca/actions/runs/26128360272.