Add optional context to PR description generation (#270)

* types: add optional context parameter to generatePullRequestDescription signature

* api: update gitApi to pass optional context to PR description generation

* http: include trimmed context in PR description API request body

* ui: add additional context input for PR generation with desktop disclosure and mobile sheet

* desktop: pass optional context to Tauri generate_pr_description command

* tauri: add optional context parameter and inject into PR description prompt

* server: read optional context from request and inject into PR description prompt

* vscode: update type signature for context parameter (compatibility only)

* fix(vscode): drop context from pr-description payload

Remove context field from PR description payload
Send only base and head to the bridge API for PR descriptions
Clarify payload compatibility across web/desktop environments

packages/ui/src/lib/gitApiHttp.ts

@@ -250,17 +250,22 @@ export async function generateCommitMessage(
 
 export async function generatePullRequestDescription(
   directory: string,
-  payload: { base: string; head: string }
+  payload: { base: string; head: string; context?: string }
 ): Promise<{ title: string; body: string }> {
-  const { base, head } = payload;
+  const { base, head, context } = payload;
   if (!base || !head) {
     throw new Error('base and head are required');
   }
 
+  const requestBody: { base: string; head: string; context?: string } = { base, head };
+  if (context?.trim()) {
+    requestBody.context = context.trim();
+  }
+
   const response = await fetch(buildUrl(`${API_BASE}/pr-description`, directory), {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ base, head }),
+    body: JSON.stringify(requestBody),
   });
 
   if (!response.ok) {