## Summary
Migrates the five-step SoulStone wizard and the TreasureMapChest remove-confirmation dialog from legacy `Gump` to the modern builder API.
Per-gump base type:
- **`SelectSkillGump` -> `DynamicGump`** -- the skill picker iterates the player's skill list and emits one button per non-zero skill, so the layout shape varies per instance.
- **`ConfirmSkillGump` -> `DynamicGump`** -- skill name uses `AosSkillBonuses.GetLabel(...)` which returns dynamic clilocs in the `1044060 + (int)skill` range, plus current/cap skill values rendered as text labels.
- **`ConfirmTransferGump` -> `DynamicGump`** -- same dynamic skill cliloc plus per-instance Base/Cap/Stored values.
- **`ConfirmRemovalGump` -> `StaticGump<ConfirmRemovalGump>`** -- only fixed clilocs (warning text, Continue, Cancel), so the layout caches.
- **`ErrorGump` -> `DynamicGump`** -- title and message clilocs are constructor parameters that vary per call site.
- **`TreasureMapChest.RemoveGump` -> `StaticGump<RemoveGump>`** -- fixed-cliloc confirmation prompt (no item list, despite the name); `Closable=false`/`Disposable=false` are now `builder.SetNoClose()`/`builder.SetNoDispose()`.
All six gumps are now `Singleton => true`, have private constructors, and expose a static `DisplayTo` entry point that validates `from`, `NetState`, and the underlying entity before constructing -- prevents the empty-gump leak. Wizard navigation between steps now goes through `DisplayTo` (e.g. `ConfirmSkillGump.DisplayTo(from, _stone, skill)` from the skill picker, `ErrorGump.DisplayTo(...)` from absorption pre-checks, `SelectSkillGump.DisplayTo(...)` from the "make another selection" button on `ConfirmSkillGump` and from `ErrorGump` bounce-back). Because each gump is Singleton, sending the same type again automatically closes any prior instance instead of stacking; the explicit `gumps.Close<T>()` chain on `OnDoubleClick` is preserved so opening the soulstone still resets any orphaned step from another wizard.
`OnResponse` now uses `in RelayInfo info`. All inline `AddX(...)` calls move to `builder.AddX(...)` inside `BuildLayout`. `Skill.Base.ToString("F1")` etc. are converted to `$"{value:F1}"` interpolation passed to `AddLabel(ReadOnlySpan<char>)`. Skill picker pagination still uses client-side `AddPage` / `GumpButtonType.Page` -- no server-state pagination to migrate.
4e565ca6da