## Summary
Migrates 10 player-facing legacy `Gump` subclasses for holiday and decorative items to the modern `DynamicGump` / `StaticGump<T>` system. All migrated gumps are `Singleton`, use private constructors gated by static `DisplayTo(...)` entry points (empty-gump rule, CLAUDE.md §13), and replace legacy `m_X` fields with `_x` per coding standards.
Per-gump base type and rationale:
- **Mistletoe.cs** — `MistletoeAddonGump` -> `StaticGump<MistletoeAddonGump>`. Fixed re-deed confirmation layout.
- **StValentinesBears.cs** — Renamed `InternalGump` -> `StValentinesBearsGump`, base `StaticGump<T>`. Fixed sign-bear layout with three text entries; legacy `m_Bear` -> `_bear`. Switched legacy `AddTextEntry(..., size)` -> `AddTextEntryLimited(...)` (modern API split).
- **Wreath.cs** — `WreathAddonGump` -> `StaticGump<WreathAddonGump>`. Fixed re-deed confirmation layout.
- **HolidayPottedPlant.cs** — Renamed `InternalGump` -> `HolidayPottedPlantGump`, base `StaticGump<T>`. Fixed plant-picker layout.
- **SnowStatue.cs** — Renamed `InternalGump` -> `SnowStatueGump`, base `StaticGump<T>`. Fixed statue-picker layout. Dropped unused `Mobile from` ctor arg.
- **TapestryOfSosaria.cs** — Renamed `InternalGump` -> `TapestryOfSosariaGump`, base `StaticGump<T>`. Single image, fixed.
- **HouseRaffleDeed.cs** — `WritOfLeaseGump` -> `DynamicGump`. Description HTML is computed per-instance from deed expiration / days-left, so layout text varies per instance. Added `Singleton => true` (was missing implicitly via legacy default).
- **SpecialScroll.cs** — Renamed `InternalGump` -> `SpecialScrollGump`, base `DynamicGump`. **Cliloc rule**: `_scroll.Message`, `_scroll.Title`, `_scroll.SkillLabel` are dynamic cliloc numbers per scroll type — `AddHtmlLocalized` bakes the cliloc number into the cached layout, so `StaticGump<T>` cannot cache it.
- **BallotBox.cs** — Renamed `InternalGump` -> `BallotBoxGump`, base `DynamicGump`. Layout shape varies: variable topic-line count, owner-vs-voter buttons, and vote-tally bars all add/remove elements. Legacy `m_Box` -> `_box`. Updated the `TopicPrompt` callbacks to call `BallotBoxGump.DisplayTo(...)` instead of allocating a new gump directly.
- **AquariumGump.cs** — `AquariumGump` -> `DynamicGump`. Per-page layout depends on each item's `LabelNumber` and (for `BaseFish`) `GetDescription()` cliloc — those vary per fish/decoration. Two `DisplayTo` overloads (auto-detect access vs explicit edit flag) to mirror the original two call sites in `Aquarium.cs`. Legacy `m_Aquarium` -> `_aquarium`.
### Skipped
- **HouseRaffleManagementGump.cs** — Skipped as **staff-only**. Only invoked via `ManagementEntry` context entry inside `HouseRaffleStone.cs`, gated by `from.AccessLevel >= AccessLevel.Seer`. Per task instructions, staff-only gumps are out of scope for this PR.
### External callers updated
- `Aquarium.cs` — Two `new AquariumGump(...)` sites swapped to `AquariumGump.DisplayTo(...)`.
All other migrated inner classes were nested in the same file and only had local references, which were updated to call the new `DisplayTo(...)` static entry point.
## Breaking Changes (New API)
ObjectPropertyList supports the following API:
```cs
list.Add(500000);
list.Add(500001, stringArgument);
list.Add("Some text");
list.Add($"Some text with {argument}");
list.Add(500002, $"{arg1}\t{arg2}");
```
## Notes
1. All API uses that require a formatter like this:
```cs
list.Add(500002, "{0}\t{1}", arg1, arg2);
```
Should be changed to use string interpolation, for example:
```cs
list.Add(500002, $"{arg1}\t{arg2}");
```
2. The following paradigm should no longer be used:
```cs
list.Add(1061170, prop.ToString()); // strength requirement ~1_val~
```
The new string interpolation API will avoid having to convert the argument to a string before writing it to the packet. Instead use the following:
```cs
list.Add(1061170, $"{prop}"); // strength requirement ~1_val~
```
### Benchmarks
```cs
| Method | Mean | Error | StdDev | Gen 0 | Allocated |
|------------------------------- |---------:|--------:|--------:|-------:|----------:|
| BenchmarkOldOPL | 241.0 ns | 0.56 ns | 0.47 ns | 0.0105 | 88 B |
| BenchmarkStringInterpolatedOPL | 199.9 ns | 2.44 ns | 2.39 ns | - | - |
```
### Changes
- [X] Removes crash in STArray.Return when array is null.
- [X] Fixes NPE in OPL when entity is null. Serial in packet will be 0 when entity is null.
- [X] Fixes NPE in AosAttributes when Parent is null.
- [X] Changes OPL to use string interpolation.
- [X] Introduces `IPropertyList` to allow extending PropertyList for other uses.
* Fixes pooled timer leaking
* Fixes `[dumptimers` command so it outputs properly, adds spacing, and stacktraces
* Adds `[Tidy]` for serializing Lists. This will remove deleted entities during world save before serializing the list.
* Adds helpers for managing Lists/Sets/Dictionaries
### New API
```cs
// Creates the list if it is null, then adds
Utility.Add(ref list, value);
Utility.Add(ref set, value);
Utility.Add(ref dict, key, value);
// Nulls the variable if the count is zero
Utility.Remove(ref list, value);
Utility.Remove(ref set, value);
Utility.Remove(ref dict, key);
// Marks entity as dirty in addition to doing the action
entity.Add(list, value);
// Marks entity as dirty, and will create list if it doesn't exist
entity.Add(ref list, value);
// Marks entity as dirty in addition to doing the action
entity.Remove(list, value);
// Marks entity as dirty, and will null the list count is zero
entity.Remove(ref list, value);
```
### Updates to [dumptimers
<img width="825" alt="Screen Shot 2021-08-14 at 2 55 10 AM" src="https://user-images.githubusercontent.com/3953314/129442449-ccf7fe14-29d6-4f3f-9366-c8eb7b9828a7.png">
After speaking with the C# devs, it is clear that code gen is not ready.
I can get around this by doing the following:
1. Creating a library
2. Splitting out the schema writing from the source generator
3. Moving the schema loading to `AdditionalFiles`
4. Writing a new post-build application using Roslyn to write the schema files after building.
- [X] Caches DateTime.NowUtc on the game loop (not other threads)
- [X] Replaces all locations where it makes sense
- [X] Adds Min/Max for `IComparable` (TimeSpan, DateTimes, etc)
Closes#261
