feat(desktop): extend deeplinks + add Raycast extension scaffold

[sungdark]

Summary

• extend desktop deeplink actions with pause/resume/toggle pause
• add deeplink actions for switching microphone and camera
• add a Raycast extension scaffold in apps/raycast that dispatches Cap deeplinks for recording controls

Deeplink actions added

• pause_recording
• resume_recording
• toggle_pause_recording
• switch_microphone
• switch_camera

Closes #1540

Greptile Summary

Extended desktop deeplink actions to support pause/resume/toggle recording and device switching (microphone/camera), then added a Raycast extension scaffold to control Cap via these deeplinks.

• Added 5 new DeepLinkAction variants in Rust: PauseRecording, ResumeRecording, TogglePauseRecording, SwitchMicrophone, SwitchCamera
• Created new Raycast extension at apps/raycast with 7 commands that dispatch Cap deeplinks
• Critical issue: fireSimpleAction in cap.ts incorrectly wraps unit variants in { type: action } instead of passing the plain string, which will cause deserialization failures for pause/resume/stop/toggle commands

Confidence Score: 2/5

• Critical bug in fireSimpleAction will break 4 of 7 Raycast commands
• The Rust backend implementation is solid, but the TypeScript deeplink dispatch function has a critical serialization bug that breaks unit variant deserialization. Commands using struct variants (start_recording, switch_camera, switch_microphone) will work, but commands using unit variants (pause_recording, resume_recording, stop_recording, toggle_pause_recording) will fail due to incorrect JSON format
• apps/raycast/src/lib/cap.ts requires immediate fix before merge

Important Files Changed

Filename	Overview
apps/desktop/src-tauri/src/deeplink_actions.rs	Added new deeplink action variants and handlers for pause/resume/toggle and device switching
apps/raycast/src/lib/cap.ts	Core deeplink dispatch logic - contains critical bug in fireSimpleAction that will break unit variant actions
apps/raycast/src/pause-recording.ts	Pause recording command - affected by fireSimpleAction bug
apps/raycast/src/resume-recording.ts	Resume recording command - affected by fireSimpleAction bug
apps/raycast/src/stop-recording.ts	Stop recording command - affected by fireSimpleAction bug
apps/raycast/src/toggle-pause-recording.ts	Toggle pause command - affected by fireSimpleAction bug

Sequence Diagram

sequenceDiagram
    participant User
    participant Raycast
    participant cap.ts
    participant Desktop App
    participant Rust Handler
    
    User->>Raycast: Trigger command
    Raycast->>cap.ts: fireSimpleAction("pause_recording")
    cap.ts->>cap.ts: JSON.stringify({ type: "pause_recording" })
    cap.ts->>Desktop App: cap-desktop://action?value=...
    Desktop App->>Rust Handler: Parse deeplink
    Rust Handler->>Rust Handler: serde_json::from_str<DeepLinkAction>
    Note over Rust Handler: FAILS - expects "pause_recording"<br/>but receives {"type":"pause_recording"}
    Rust Handler-->>User: Error: Failed to parse deeplink
    
    Note over cap.ts,Rust Handler: FIX: Pass action string directly,<br/>not wrapped in object

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_{Last reviewed commit: a595e0e}

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[tembo]

DeepLinkAction uses Serde's default external tagging, so unit variants need to be JSON strings (e.g. "pause_recording"), not { type: "pause_recording" }.

Suggested change

	await dispatchAction({ type: action });
	await dispatchAction(action);

[tembo]

If captureName is empty, this will dispatch an action that the desktop app can't resolve (and the user gets a pretty opaque failure). Consider validating before dispatch.

Suggested change

	async function onSubmit(values: Values) {
	const captureMode =
	values.captureType === "screen"
	? { screen: values.captureName }
	: { window: values.captureName };
	async function onSubmit(values: Values) {
	const captureName = values.captureName.trim();
	if (!captureName) {
	await showHUD("Cap: capture name required");
	return;
	}
	const captureMode =
	values.captureType === "screen" ? { screen: captureName } : { window: captureName };

[greptile-apps]

_{11 files reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

Serde deserializes unit enum variants from plain JSON strings, not objects. { type: action } should be just action

Suggested change

	export async function fireSimpleAction(action: string) {
	await dispatchAction({ type: action });
	await showHUD(`Cap: ${action}`);
	export async function fireSimpleAction(action: string) {
	await dispatchAction(action);
	await showHUD(`Cap: ${action}`);
	}

Prompt To Fix With AI

This is a comment left during a code review.
Path: apps/raycast/src/lib/cap.ts
Line: 13-15

Comment:
Serde deserializes unit enum variants from plain JSON strings, not objects. `{ type: action }` should be just `action`

```suggestion
export async function fireSimpleAction(action: string) {
  await dispatchAction(action);
  await showHUD(`Cap: ${action}`);
}
```

How can I resolve this? If you propose a fix, please make it concise.