acp: Support session modes (e.g. CC plan mode) (#37632)

Adds support for [ACP session
modes](https://github.com/zed-industries/agent-client-protocol/pull/67)
enabling plan and other permission modes in CC:


https://github.com/user-attachments/assets/dea18d82-4da6-465e-983b-02b77c6dcf15


Release Notes:

- Claude Code: Add support for plan mode, and all other permission modes

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>

crates/agent2/src/agent.rs

@@ -771,7 +771,9 @@ impl NativeAgentConnection {
                                 response,
                             }) => {
                                 let outcome_task = acp_thread.update(cx, |thread, cx| {
-                                    thread.request_tool_call_authorization(tool_call, options, cx)
+                                    thread.request_tool_call_authorization(
+                                        tool_call, options, true, cx,
+                                    )
                                 })??;
                                 cx.background_spawn(async move {
                                     if let acp::RequestPermissionOutcome::Selected { option_id } =