feat: Add more /review options (#3961)

Adds the following options:

1. Review current changes
2. Review a specific commit
3. Review against a base branch (PR style)
4. Custom instructions

<img width="487" height="330" alt="Screenshot 2025-09-20 at 2 11 36 PM"
src="https://github.com/user-attachments/assets/edb0aaa5-5747-47fa-881f-cc4c4f7fe8bc"
/>

---

\+ Adds the following UI helpers:

1. Makes list selection searchable
2. Adds navigation to the bottom pane, so you could add a stack of
popups
3. Basic custom prompt view

codex-rs/tui/src/app_event.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use codex_core::protocol::ConversationPathResponseEvent;
 use codex_core::protocol::Event;
 use codex_file_search::FileMatch;
@@ -65,4 +67,16 @@ pub(crate) enum AppEvent {
 
     /// Forwarded conversation history snapshot from the current conversation.
     ConversationHistory(ConversationPathResponseEvent),
+
+    /// Open the branch picker option from the review popup.
+    OpenReviewBranchPicker(PathBuf),
+
+    /// Open the commit picker option from the review popup.
+    OpenReviewCommitPicker(PathBuf),
+
+    /// Open the custom prompt option from the review popup.
+    OpenReviewCustomPrompt,
+
+    /// Open the top-level review presets popup.
+    OpenReviewPopup,
 }