Feature: stream recording support

[Jayian1890]

Summary

Adds stream recording support to OpenNOW, allowing users to record their GeForce NOW sessions directly from the client. Recordings are captured via the browser's MediaRecorder API, streamed in chunks to the main process, and saved to disk as MP4 or WebM files.

Changes

Main Process (src/main/index.ts)

• Enabled the MediaRecorderEnableMp4Muxer Chromium feature flag to support MP4 output via MediaRecorder (Chromium 127+).
• Added a full recording pipeline with IPC handlers:
  • RECORDING_BEGIN — allocates a temp write stream and returns a recordingId
  • RECORDING_CHUNK — streams binary chunks from the renderer to the temp file
  • RECORDING_FINISH — finalises the recording, encodes an optional thumbnail, renames the temp file to its final timestamped name (with duration encoded), and enforces a 20-recording limit (oldest auto-deleted)
  • RECORDING_ABORT — cancels an in-progress recording and removes the temp file
  • RECORDING_LIST — reads the recordings directory and returns metadata for all saved recordings (including base64-encoded thumbnails)
  • RECORDING_DELETE — deletes a recording and its thumbnail
  • RECORDING_SHOW_IN_FOLDER — reveals a recording in the system file manager via shell.showItemInFolder
• Recordings are saved to ~/Pictures/OpenNOW/Recordings/ with filenames encoding the game title, timestamp, and duration.
• Input is sanitised to prevent path traversal (assertSafeRecordingId).

Preload (src/preload/index.ts)

• Exposed all seven recording API methods on window.openNow: beginRecording, sendRecordingChunk, finishRecording, abortRecording, listRecordings, deleteRecording, showRecordingInFolder.

Renderer — StreamView (src/renderer/src/components/StreamView.tsx)

• Added recording state: isRecording, recordingDurationMs, recordings, recordingError.
• Implemented startRecording / stopRecording using MediaRecorder on the stream's video track, with chunk streaming to the main process.
• Live recording timer ticks every second while recording is active.
• Recording controls displayed in the sidebar (start/stop button, duration display, error feedback).
• Recordings gallery in the sidebar — lists saved recordings with thumbnail, duration, file size, game title, date, and actions (open in folder, delete).
• Configurable keyboard shortcut to toggle recording, with conflict detection against existing shortcuts.
• recordingApiAvailable guard ensures controls are only shown when the preload API is present.

App (src/renderer/src/App.tsx)

• Wired onRecordingShortcutChange prop to persist the recording shortcut via settings.

Settings (src/main/settings.ts)

• Added recording shortcut key to the persisted settings schema.

Shared Types (src/shared/gfn.ts, src/shared/ipc.ts)

• Added RecordingEntry, RecordingBeginRequest, RecordingBeginResult, RecordingChunkRequest, RecordingFinishRequest, RecordingAbortRequest, RecordingDeleteRequest interfaces.
• Added shortcutToggleRecording to the OpenNowAPI interface.
• Added RECORDING_* IPC channel constants.

Styles (src/renderer/src/styles.css)

• Added styles for the recording indicator (pulsing red dot), recording controls, and recording card gallery items in the sidebar.

Notes

• The MP4 muxer flag is required for MP4 output; the implementation falls back to WebM if MP4 is not supported by the browser.
• The recording limit is capped at 20 entries; exceeding this auto-deletes the oldest recording.
• Thumbnails are captured as JPEG and stored alongside the video file (<stem>-thumb.jpg).