chore: add channel history loading and refactor GetChannelHistory with offset to changelog

docs/changelog/v0.2.10.md

@@ -1,10 +1,11 @@
 # v0.2.10
 
-Follow-up patch release for v0.2.9 addressing auto-updater regressions, adding a command palette, and input polish.
+Follow-up patch release for v0.2.9 addressing auto-updater regressions, adding a command palette, infinite-scroll message history, and input polish.
 
 ## New Features
 
 - Command palette — press Ctrl+K from the message input (or anywhere in the main window) to open a searchable dialog for navigating channels and triggering app actions (connect, disconnect, logout, profile, status, create/delete channel, saved servers, toggle users panel, check for updates, quit). Fuzzy matches against both the label and the underlying key so typing `ch` surfaces channel actions alongside `#channel` entries
+- Scroll-to-load message history — scrolling to the top of a channel now fetches the next batch of older messages in the background (previously only the most recent 100 messages were available). Duplicate messages are filtered by ID, a per-channel guard prevents concurrent fetches, and the scroll position is preserved after the prepend so your reading position doesn't jump
 
 ## Bug Fixes
 
@@ -16,3 +17,5 @@ Follow-up patch release for v0.2.9 addressing auto-updater regressions, adding a
 ## Refactoring
 
 - Move search-dialog dispatch out of `MainWindow` into `AppOrchestrator` — `MainWindow` now just raises `OnSearchRequested`, keeping the view dumb and letting the orchestrator own navigation/action routing
+- `ChatHub.GetChannelHistory` and `IChatService.GetChannelHistoryAsync` gain an additional `offset` parameter for paginated history loading (defaults to `0` — existing callers are unaffected)
+- `ValidationConstants.MaxHistoryCount` raised from `100` to `200` so power users and paginated fetches can request larger batches; `DefaultHistoryCount` stays at `100`