chore(app-server): delete v1 RPC methods and notifications (#13375)

## Summary
This removes the old app-server v1 methods and notifications we no
longer need, while keeping the small set the main codex app client still
depends on for now.

The remaining legacy surface is:
- `initialize`
- `getConversationSummary`
- `getAuthStatus`
- `gitDiffToRemote`
- `fuzzyFileSearch`
- `fuzzyFileSearch/sessionStart`
- `fuzzyFileSearch/sessionUpdate`
- `fuzzyFileSearch/sessionStop`

And the raw `codex/event/*` notifications emitted from core. These
notifications will be removed in a followup PR.

## What changed
- removed deprecated v1 request variants from the protocol and
app-server dispatcher
- removed deprecated typed notifications: `authStatusChange`,
`loginChatGptComplete`, and `sessionConfigured`
- updated the app-server test client to use v2 flows instead of deleted
v1 flows
- deleted legacy-only app-server test suites and added focused coverage
for `getConversationSummary`
- regenerated app-server schema fixtures and updated the MCP interface
docs to match the remaining compatibility surface

## Testing
- `just write-app-server-schema`
- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server`

codex-rs/app-server/tests/suite/v2/realtime_conversation.rs

@@ -5,7 +5,7 @@ use app_test_support::create_mock_responses_server_sequence_unchecked;
 use app_test_support::to_response;
 use codex_app_server_protocol::JSONRPCError;
 use codex_app_server_protocol::JSONRPCResponse;
-use codex_app_server_protocol::LoginApiKeyParams;
+use codex_app_server_protocol::LoginAccountResponse;
 use codex_app_server_protocol::RequestId;
 use codex_app_server_protocol::ThreadRealtimeAppendAudioParams;
 use codex_app_server_protocol::ThreadRealtimeAppendAudioResponse;
@@ -350,17 +350,14 @@ async fn read_notification<T: DeserializeOwned>(mcp: &mut McpProcess, method: &s
 }
 
 async fn login_with_api_key(mcp: &mut McpProcess, api_key: &str) -> Result<()> {
-    let request_id = mcp
-        .send_login_api_key_request(LoginApiKeyParams {
-            api_key: api_key.to_string(),
-        })
-        .await?;
-
-    timeout(
+    let request_id = mcp.send_login_account_api_key_request(api_key).await?;
+    let response: JSONRPCResponse = timeout(
         DEFAULT_TIMEOUT,
         mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
     )
     .await??;
+    let login: LoginAccountResponse = to_response(response)?;
+    assert_eq!(login, LoginAccountResponse::ApiKey {});
 
     Ok(())
 }