## Summary
Migrates three legacy `Gump`-based dialogs to the modern builder API:
- **PlayerBBGump** (`Projects/UOContent/Items/Misc/PlayerBulletinBoards.cs`) — `DynamicGump`. The bulletin board renders a different post per page (variable per-instance state), so the layout cannot be cached. Now `Singleton`, with a private constructor and a static `DisplayTo` entry point. Scroll/banish/delete/post-props buttons mutate `_page` and self-refresh via `SendGump(this)` instead of allocating a fresh gump on every click. Prompt-driven flows (post message / set title / post greeting) re-enter through `DisplayTo` after the prompt completes.
- **MessageGump** + **OldMessageGump** (`Projects/UOContent/Items/Skill Items/Fishing/Misc/SOS.cs`) — `StaticGump<T>`. Both render a fixed structure (background + body + button) where only the formatted sextant coordinate string varies per SOS bottle. The cliloc IDs that *appear in the gump packet* are constant (`MessageGump` uses 1018326; `OldMessageGump` uses no `AddHtmlLocalized` at all — its message is pre-formatted into a string before construction), so the layout cache is safe per the cliloc rule. The varying coordinate text is fed through an HTML placeholder via `BuildStrings`. Both gumps are now `Singleton` with private constructors and static `DisplayTo` entry points.
- **ShardPollGump** (`Projects/UOContent/Misc/ShardPoller.cs`) — `DynamicGump`. The gump's structure changes both with the number of poll options (variable loop) and with the `editing` flag (admin sees radios + add-option row + result percentages; players see only radios). The dual-purpose view is preserved as a single `DynamicGump` with the `editing` flag still controlling layout shape — staff path verified to still render the editor with the totals header, vote percentages, and "Create new option" radio. `Closable = false` becomes `builder.SetNoClose()`. Now `Singleton`, with private constructor and a `DisplayTo` that returns the gump instance so `EventSink_Login_Callback` can still call `QueuePoll` on it. The cancel/edit re-issue paths use `SendGump(this)` for self-refresh; the queued login flow uses `DisplayTo` so each queued poll gets its own gump.
External callers (`OnDoubleClick`, `PostPrompt`, `SetTitlePrompt`, `ShardPollPrompt`, `EventSink_Login_Callback`, the Timer-delayed queued poll send) all updated to use the new `DisplayTo` entry points. Legacy `m_X` field naming was already absent in two of the three files; the bulletin board fields kept their `_camelCase` names. `dotnet build Projects/UOContent/UOContent.csproj` reports 0 warnings, 0 errors.
