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 a new persisted pin/unpin write path into the native chat store and surfaces it via immediate UI actions with undo, which could affect chat metadata consistency across sessions. Changes are localized but touch storage JSON updates and user-facing state transitions.

Overview
Enables the per-row Pin/Unpin action in chat history to immediately move chats between Pinned and Recent, and shows a snackbar with Undo after toggling.

Adds a new ChatHistoryRepository.setPinned flow backed by native storage (DuckAiChatStore.pinChat/unpinChat) that updates the stored chat JSON’s pinned field, plus ViewModel/fragment wiring (messageEvents) and new tests validating state changes and persistence behavior.

^{Reviewed by Cursor Bugbot for commit 83e7fe3. Bugbot is set up for automated code reviews on this repo. Configure here.}

[GerardPaligot]

• Wire per-row Pin/Unpin in chat history overflow menu #8604 👈 (View in Graphite)
• develop

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[malmstein]

Works as expected, left a few comments but nothing blocker