Wire per-row Pin/Unpin in chat history overflow menu

[GerardPaligot]

Task/Issue URL: https://app.asana.com/1/137249556945/project/72649045549333/task/1214820120386824?focus=true

Description

Wires the Pin / Unpin action on the Duck.ai chat history screen so a chat actually moves between the Pinned and Recent sections. The toggle fires immediately with no confirmation; a snackbar with Undo appears so a mistap is recoverable. State is persisted via the native chat store so the same Pinned/Recent split shows on next open and on Duck.ai itself.

Steps to test this PR

Note

Prerequisites:

• Install Internal Debug.
• In Settings → Developer Settings → Feature Flags, confirm duckAiChatHistory (self, historyScreen) is ON and duckChat → useNativeStorageChatData is ON.
• Create at least 2 chats in Duck.ai so there's something to pin.

Happy path

• Open the Chats screen → tap the 3-dot on a Recent row → tap Pin → confirm the row moves to a Pinned section above Recent and a "Chat pinned" snackbar appears with an Undo action.
• Tap the 3-dot on a Pinned row → tap Unpin → confirm the row moves back to Recent and a "Chat unpinned" snackbar appears with Undo.
• Trigger a pin → tap Undo before the snackbar auto-dismisses → confirm the row returns to its original section.
• Trigger an unpin → tap Undo → confirm the row returns to the Pinned section.

Persistence

• Pin a chat, close and reopen the Chats screen → confirm the chat is still in the Pinned section.
• Pin a chat on Android, then open the same chat on Duck.ai web → confirm it shows as pinned there too (and vice versa).

UI changes

Before	After
N/A

---

Note

Medium Risk
Adds new pin/unpin write path that mutates stored chat JSON and updates UI ordering; mistakes could cause incorrect pinned state or lost updates across sessions.

Overview
Enables Pin/Unpin from the chat history row overflow menu: the action now toggles a chat between Pinned and Recent and shows a snackbar with Undo.

This adds a setPinned persistence API through ChatHistoryRepository into DuckAiChatStore (writing the pinned flag into the stored JSON), introduces a MessageEvent.PinToggled stream for snackbar messaging, and adds new strings plus unit tests covering toggle/undo and store JSON updates.

^{Reviewed by Cursor Bugbot for commit 23dda12. Bugbot is set up for automated code reviews on this repo. Configure here.}

[GerardPaligot]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Wire per-row Pin/Unpin in chat history overflow menu #8604 👈 (View in Graphite)
• Wire per-row Rename in chat history overflow menu #8599
• Add fire actions to native chat history screen #8579
• Data-clearing additions to delete selected Duck.ai chats #8582
• develop

This stack of pull requests is managed by Graphite. Learn more about stacking.