## Why
Delta world saves re-serialize an entity only when it has been marked dirty. An audit of the generated classes found three ways serialized state changes without a mark; this PR closes the ones that do not need a new generator package.
## What
- **Custom `[SerializableProperty]` setters mark dirty.** Twelve hand-written setters assigned their backing field without `this.MarkDirty()`. `PlagueBeastLord.OpenedBy` was an auto-property carrying the attribute with no backing field at all; it is now a generated field with the same name, order and command-property exposure.
- **Generated sub-objects are linked to their owner.** Without a `[DirtyTrackingEntity]` member the generator emits setters that mark nothing. Eight entity-owned sub-objects now carry the link and receive the owner through the constructor the generator calls: `BOBFilter` (owner is `IEntity`: a `PlayerMobile` or a `BulkOrderBook`), `BOBLargeSubEntry`, `PuzzleChestSolution` and `PuzzleChestSolutionAndTime`, `TalismanAttribute` (the random factories now take the talisman), `VendorItem`, `PlayerBBMessage`, `RaffleEntry`, `ShardPollOption`. Migration schemas were regenerated with the pinned tool; the only change is the value rule argument becoming `DeserializationRequiresParent`.
- **BaseVendor uses the generator; restock amounts are no longer persisted.** The only state it wrote was which buy entries had grown restock amounts, packed by index into the live `SBInfos` tables. Restock is transient now and rebuilds on load; version 1 records are read and discarded through the legacy path. Every vendor subclass now serializes through a generated chain.
## Generator 4.1.0
This PR adopts SerializationGenerator 4.1.0 (modernuo/SerializationGenerator#55): SG3019/SG3020 diagnostics, `[VolatileSerializedState]`, `StopXxx()` timer helpers, and owner-constructor preference for sub-objects (so dictionary values are constructed with their owner; the 4.0.0 relink fallback is gone). `PlayerVendor.v3.json` gains `DeserializationRequiresParent` for its `VendorItem` values so the migration content struct constructs them with their vendor.
SG3019 is an error under `TreatWarningsAsErrors` and generator diagnostics ignore pragmas, so the five contexts that live in whole-file player-keyed persistences (`ChampionTitle`, `ChampionTitleContext`, `MurderContext`, `VirtueContext`, `JailRecord`) now carry a `[DirtyTrackingEntity]` link to their `PlayerMobile`, which is where they will live once those blobs move onto the player record. `JailSystem.EmptyRecord` keeps a null player (`[CanBeNull]`). `ChampionTitle` needs both a context and a player constructor because the generator resolves the rule against the containing type but emits the call with the parent field; a comment in the file records this.
## Wire format
Unchanged. No version bumps except `BaseVendor` 1 to 2 (which now writes nothing of its own). Schema diffs are rule-argument only (`DeserializationRequiresParent`).
## Testing
Server.Tests 848 passed, UOContent.Tests 759 passed.
## Summary
Phase 3 of the anchored-time work: **every actively-written delta-time value in the engine now stores an anchored timestamp** — absolute on the wire, shifted forward by the downtime at load. Remaining time survives restarts (as delta did), and unlike delta, the bytes do not change on every save, so an idle world serializes identically save after save.
The answer to "is it possible everywhere": **yes** — including the one case that looked impossible.
## The GenericPersistence problem, solved
`GenericPersistence` bins (`Virtues.bin`, `StealableArtifacts.bin`, …) are raw payloads with no idx header, so they have no anchor of their own — anchored reads there would silently apply zero shift. But the anchor is a property of the **save**, not the file: every file in one save shares one `World.SaveStartTime`, and `Persistence.Load` reads **all** entity indexes (phase 1) before **any** persistence payload (phase 2). So the idx v5 header stamps a save-wide `World.LoadTimeShift`, and generic persistence readers inherit it. No file-format change, no per-bin header, old bins unaffected.
## Converted
- **Item v10 → v11**: `LastMoved` — previously whole-minute delta, rewritten every save for every item, the single largest source of idle-save churn — and `DecayResetTime` (retiring the TODO from #2583). **Mobile v37 → v38**: the three stat-gain stamps. **BaseCreature v20 → v21**: `SummonEnd`.
- **17 code-generated classes** (`[DeltaDateTime]` → `[AnchoredDateTime]`, version bump + `MigrateFrom` each): the five field spells, TransientItem, VirtueContext (×7 fields), PuzzleChestSolutionAndTime, BaseCamp, BaseBoat, RentedVendor, PlayerVendor, Ethics Player, Sheep, StarRoomGate, ChampionSpawn (×3), Corpse (`TimeOfDeath`, v19). The `MigrateFrom` bodies were generated from each class's current migration schema and are compiler-verified; VirtueContext's save-flagged nullables fall back to the same defaults the old deserialize left in place. Corpse's six migrations moved to a new `Corpse.Migrations.cs`.
- **Hand-written sites**: StealableArtifacts (v2), VendorInventory (v1), ML quest objectives (persistence v3) — each gated on its own version.
**Not converted, deliberately**: the ~25 read-only `ReadDeltaTime` sites in legacy version fallbacks and migration replays — they decode existing old bytes and must never change. `[DeltaDateTime]`/`WriteDeltaTime` remain available for them.
## Verification
- Build 0 errors / 0 warnings; **837 + 708 tests green**.
- Schema regeneration produced exactly the 17 expected new `vN.json` files (all `AnchoredTime` rule args), nothing else touched.
- **New acceptance tests** pin the point of the whole effort: serializing the same item at two save times **5 hours apart produces byte-identical output**, and `LastMoved`/`DecayResetTime` round-trip **exactly** at sub-minute precision (the old minutes encoding destroyed both properties).
## Notes for review
- `LastMoved` grows from a 1–3 byte encoded minutes value to 8-byte ticks per item — the price of byte-stability; it repays itself in incremental-save behavior since unchanged items now produce unchanged bytes.
- BaseEscortable-style semantics are unchanged: anchored shift preserves *remaining* time exactly, the same contract delta provided, so no gameplay-visible behavior changes — deadlines simply stop being consumed by downtime that delta already protected against, now with stable bytes.
## Enforcement
`WriteDeltaTime` is now `[Obsolete]` (interface + implementation). With the repo's warnings-as-errors, any new delta-time write — hand-written or emitted by a still-unconverted `[DeltaDateTime]` field — fails the build, with the migration instructions in the message. That the full solution still builds with **zero warnings** is itself the proof no active delta writer survived the conversion. `ReadDeltaTime` deliberately stays un-attributed: its remaining callers decode existing old bytes and are correct forever; its XML docs now state the legacy-decode-only contract.
Kamron Batman