feat: add session deletion with per-provider cleanup and path safety

Add delete_session Tauri command dispatching to provider-specific deletion
logic for all 5 providers (Claude, Codex, Gemini, OpenCode, OpenClaw).
Includes path traversal protection via canonicalize + starts_with validation,
session ID verification against file contents, frontend confirmation dialog
with optimistic cache updates, i18n keys (zh/en/ja), and component tests.

src/lib/api/sessions.ts

@@ -1,6 +1,12 @@
 import { invoke } from "@tauri-apps/api/core";
 import type { SessionMessage, SessionMeta } from "@/types";
 
+export interface DeleteSessionOptions {
+  providerId: string;
+  sessionId: string;
+  sourcePath: string;
+}
+
 export const sessionsApi = {
   async list(): Promise<SessionMeta[]> {
     return await invoke("list_sessions");
@@ -13,6 +19,15 @@ export const sessionsApi = {
     return await invoke("get_session_messages", { providerId, sourcePath });
   },
 
+  async delete(options: DeleteSessionOptions): Promise<boolean> {
+    const { providerId, sessionId, sourcePath } = options;
+    return await invoke("delete_session", {
+      providerId,
+      sessionId,
+      sourcePath,
+    });
+  },
+
   async launchTerminal(options: {
     command: string;
     cwd?: string | null;