tui: improve rendering of search cell (#8273)

before:

<img width="795" height="150" alt="Screenshot 2025-12-18 at 10 48 01 AM"
src="https://github.com/user-attachments/assets/6f4d8856-b4c2-4e2a-b60a-b86f82b956a0"
/>

after:

<img width="795" height="150" alt="Screenshot 2025-12-18 at 10 48 39 AM"
src="https://github.com/user-attachments/assets/dd0d167a-5d09-4bb7-9d36-95a2eb1aaa83"
/>

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__web_search_history_cell_snapshot.snap

@@ -0,0 +1,6 @@
+---
+source: tui/src/history_cell.rs
+expression: rendered
+---
+• Searched example search query with several generic words to
+  exercise wrapping

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__web_search_history_cell_transcript_snapshot.snap

@@ -0,0 +1,6 @@
+---
+source: tui/src/history_cell.rs
+expression: rendered
+---
+• Searched example search query with several generic words to
+  exercise wrapping