Clip requested action text in narrow panes

[moirahuang]

Description

Clips requested action row body content to the same shrinkable bounds as the rounded row background. This prevents long action text (for example file paths like skills-lock.json:6) from painting past the row background when the pane is narrow.

Linked Issue

• The linked issue is labeled ready-to-spec or ready-to-implement.
• Where appropriate, screenshots or a short video of the implementation are included below (especially for user-visible or UI changes).

Slack feedback: https://warp-core.slack.com/archives/C08KTPNQN65/p1779141317356059

Testing

• cargo fmt -p warp --check --manifest-path /workspace/warp/Cargo.toml
• cargo check -p warp --manifest-path /workspace/warp/Cargo.toml
• cargo clippy -p warp --all-targets --manifest-path /workspace/warp/Cargo.toml -- -D warnings (blocked by unrelated existing clippy errors in warpui_core/warpui; the first failures are clippy::collapsible_match, clippy::unnecessary_unwrap, and clippy::unnecessary_sort_by outside this change)
• I have manually tested my changes locally with ./script/run (not run in this headless sandbox)

Screenshots / Videos

Original Slack screenshot showed action text overflowing past the rounded row background at narrow pane widths. I was not able to capture a local UI screenshot in this headless sandbox.

Agent Mode

• Warp Agent Mode - This PR was created via Warp's AI Agent Mode

CHANGELOG-BUG-FIX: Fixed AI inline action row text overflowing past its rounded background in narrow panes.

Conversation: https://staging.warp.dev/conversation/d4528770-a5bc-4402-a923-0b994ca20545
Run: https://oz.staging.warp.dev/runs/019e3d16-30b6-76af-a06f-bbc828128c77
This PR was generated with Oz.