Move test scaffolding out of the deploy path

BridgeSeeder and BridgeProbe are not part of the bridge, but living under
overlay/Scripts/Custom/ meant deploy.ps1 would copy them onto any server we
deployed to. Move them to tools/scaffolding/, which nothing syncs.

overlay/Config/Bridge.cfg now carries the bridge's own settings (host, port,
queue cap, sweep intervals) rather than the scaffolding flags. Config.Get
returns false for a missing key, so a deployed server never runs the seeder or
probe even if their .cs files are present.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/scaffolding/README.md

@@ -0,0 +1,63 @@
+# Test scaffolding
+
+**Not part of the bridge. Never deployed.** `deploy.ps1` only copies `overlay/`, so nothing here reaches a server unless you put it there by hand.
+
+These two scripts produced the measured budget in `docs/PLAN.md` §1. They are kept because those numbers should be reproducible, and because re-running the probe is the only honest way to check whether a change to the plugin's read path got more expensive.
+
+| File | Server path when testing | What |
+|------|--------------------------|------|
+| `BridgeSeeder.cs` | `Scripts/Custom/BridgeSeeder.cs` | Populates a synthetic world: 50 accounts, 150 characters, 30 houses, 30 player vendors with 40 listings each. |
+| `BridgeProbe.cs` | `Scripts/Custom/BridgeProbe.cs` | Times every read the plugin performs, on the Core thread. Read-only. |
+
+## Using them
+
+Copy both into `Scripts/Custom/`, then append the flags to `Config/Bridge.cfg`:
+
+```ini
+SeedOnStart=True
+CensusOnStart=False
+ProbeOnStart=False
+```
+
+Boot once to seed and save, then set `SeedOnStart=False`. `CensusOnStart` reports what the loaded world actually contains; `ProbeOnStart` prints timings two seconds after `ServerStarted`.
+
+Because `Config.Get` returns `false` for a missing key, a server whose `Bridge.cfg` lacks these keys never runs the scaffolding — even if the `.cs` files are sitting in `Scripts/Custom/`. That is the safety net, not an excuse to ship them.
+
+In-game, `[seedworld` and `[unseedworld` (Administrator) do the same work on a live shard.
+
+## Back up `Saves/` first
+
+`[seedworld` and `SeedOnStart` **write to the live world**. Copy `Saves/` somewhere outside the repo before running either. `Backups/Automatic` is rotated by `AutoSave.cs` and `Backups/Temp` is deleted outright, so neither is a safe destination.
+
+`[unseedworld` deletes every `seed_*` account, which takes their characters and houses with it — but not necessarily their `PlayerVendor` mobiles. Restoring a backup is the reliable reset.
+
+## What the seeder had to work around
+
+Worth knowing before you trust its output:
+
+- **Plate needs strength.** `BaseArmor.CanEquip` rejects when `from.Str < strReq` (`PlateChest` needs 95). A rejected `EquipItem` leaves the item parentless, and the `Cleanup` pass later deletes it en masse. The seeder gives characters `Str` 100–125 and deletes any item whose equip is refused, rather than orphaning it.
+- **`VendorItem.Price` is get-only** and `PlayerVendor.SetVendorItem` is private. Dropping an item into a vendor's pack fires `OnSubItemAdded`, which registers the item at the default price of 999. The seeder reaches `SetVendorItem` by reflection to set a real price. Acceptable in throwaway scaffolding; do not do this in the plugin.
+- **Houses only decay when condemned.** `BaseHouse.CanDecay` is true only for `DecayType.Condemned` or `ManualRefresh`. An active owner's newest house is `AutoRefresh` and never decays. The seeder backdates 18 accounts past `Account.InactiveDuration` (180 days) to condemn them, then forces stages with `SetDynamicDecay` — not by backdating `LastRefreshed`, because `DynamicDecay.Enabled` is true on this expansion and `GetOldDecayLevel` is unreachable.
+
+## Reference output
+
+Census after a fresh load of the seeded world:
+
+```
+[BridgeSeeder] houses=35
+[BridgeSeeder]   decay Ageless 13, Slightly 3, Somewhat 7, Fairly 3, Greatly 3, IDOC 6
+[BridgeSeeder] seeded chars=150 avgEquipped=8.00 naked=0
+[BridgeSeeder] playervendors=30
+```
+
+Probe, best-of-20 on the Core thread:
+
+```
+[BridgeProbe] char.profile      0.069 ms/char     2386 bytes json
+[BridgeProbe] vitals sweep      0.223 ms  for 150 chars   (0.0015 ms/char)
+[BridgeProbe] decay sweep       0.007 ms  for 35 houses   (0.0002 ms/house)
+[BridgeProbe] economy sweep     0.001 ms  for 51 accounts (supply 110,478,209 gold)
+[BridgeProbe] vendor snap       0.343 ms  for 30 vendors  (1200 listings)
+```
+
+Seeded characters carry 8 items with ~6 mods each and ~12 trained skills. A real endgame character has more of both, so profile cost and payload are a **floor** — budget 2–4× for a fully-kitted character.