fix: enrich session_end lifecycle hooks (#59715)

Merged via squash.

Prepared head SHA: b3ef62b973
Co-authored-by: jalehman <550978+jalehman@users.noreply.github.com>
Co-authored-by: jalehman <550978+jalehman@users.noreply.github.com>
Reviewed-by: @jalehman

src/plugins/types.ts

@@ -2482,11 +2482,25 @@ export type PluginHookSessionStartEvent = {
 };
 
 // session_end hook
+export type PluginHookSessionEndReason =
+  | "new"
+  | "reset"
+  | "idle"
+  | "daily"
+  | "compaction"
+  | "deleted"
+  | "unknown";
+
 export type PluginHookSessionEndEvent = {
   sessionId: string;
   sessionKey?: string;
   messageCount: number;
   durationMs?: number;
+  reason?: PluginHookSessionEndReason;
+  sessionFile?: string;
+  transcriptArchived?: boolean;
+  nextSessionId?: string;
+  nextSessionKey?: string;
 };
 
 // Subagent context

src/plugins/wired-hooks-session.test.ts

@@ -40,7 +40,15 @@ describe("session hook runner methods", () => {
     {
       name: "runSessionEnd invokes registered session_end hooks",
       hookName: "session_end" as const,
-      event: { sessionId: "abc-123", sessionKey: "agent:main:abc", messageCount: 42 },
+      event: {
+        sessionId: "abc-123",
+        sessionKey: "agent:main:abc",
+        messageCount: 42,
+        reason: "daily" as const,
+        sessionFile: "/tmp/abc-123.jsonl.reset.2026-04-02T10-00-00.000Z",
+        transcriptArchived: true,
+        nextSessionId: "def-456",
+      },
     },
   ] as const)("$name", async ({ hookName, event }) => {
     await expectSessionHookCall({ hookName, event, sessionCtx });