Deep link: add prompt (#1669)

Example:
open
"dyad://add-prompt?data=eyJ0aXRsZSI6IlRlc3QgUHJvbXB0IiwiZGVzY3JpcHRpb24iOiJBIHRlc3QgcHJvbXB0IGZyb20gZGVlcCBsaW5rIiwiY29udGVudCI6IlRoaXMgaXMgdGhlIGNvbnRlbnQgb2YgdGhlIHByb21wdC4ifQ%3D%3D"

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds dyad://add-prompt deep link that navigates to Library and opens a
prefilled Create Prompt dialog from base64 JSON.
> 
> - **Deep Link Handling**
> - Parse `dyad://add-prompt?data=<base64-json>` in `src/main.ts`;
validate with `AddPromptDataSchema` and send `deep-link-received` with
payload.
> - Extend `DeepLinkContext` to navigate to `/library` on `add-prompt`.
> - **Library/Dialogs**
> - Add controlled open state and `prefillData` support to
`CreateOrEditPromptDialog` and `CreatePromptDialog`
(`src/components/CreatePromptDialog.tsx`).
> - In `src/pages/library.tsx`, listen for `add-prompt` deep link,
prefill form, open dialog, and clear deep-link state.
> - **Schemas**
> - Define `AddPromptDataSchema`, `AddPromptPayload`, and
`AddPromptDeepLinkData` in `src/ipc/deep_link_data.ts` and include in
`DeepLinkData` union.
> - **E2E Tests**
> - Add Playwright test `e2e-tests/add_prompt_deep_link.spec.ts` and
ARIA snapshot to verify deep link opens prefilled dialog and saves
prompt.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
1ddb12306cfca195682c8a1b719f60093b858d54. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

src/ipc/deep_link_data.ts

@@ -20,8 +20,23 @@ export type AddMcpServerDeepLinkData = {
   type: "add-mcp-server";
   payload: AddMcpServerPayload;
 };
+
+export const AddPromptDataSchema = z.object({
+  title: z.string(),
+  description: z.string(),
+  content: z.string(),
+});
+
+export type AddPromptPayload = z.infer<typeof AddPromptDataSchema>;
+
+export type AddPromptDeepLinkData = {
+  type: "add-prompt";
+  payload: AddPromptPayload;
+};
+
 export type DeepLinkData =
   | AddMcpServerDeepLinkData
+  | AddPromptDeepLinkData
   | {
       type: string;
     };