feat: stage 2, the NPC and its API (API 2)

RunicNPC now spawns its own NPC: Rust's scientist with its ScientistNPC and
ScientistBrain swapped for ours, copying a fixed field list generated from
Rust's unmodified assembly (D232, tools/fieldlist). Profiles live in
data/RunicNPC/profiles.json in the approved shape (D238); placements persist
with each/group respawn (D236) and wait for a missing profile or route
(D237); roamers wander, follow Rust's monument paths, or walk a route (D233,
D234), with our own chase where Rust's needs an AI zone; sentries hold their
spot; NPCs walk home and sleep past 160 m of any player (D235). Spawns wait
for the navmesh and are spread over frames; caps are off by default and the
cost warning is shown instead (D227). The whole PLAN.md section 4 API and its
hooks are in, documented in docs/runicnpc/API.md.

tools/RunicNpcTest.cs is the stage 2 harness; every group passed on both
rigs, and after a plugin reload and a server restart. checkPlugin no longer
counts an override (RunicNpcPlayer.OnDied) as a hook.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

README.md

@@ -7,8 +7,9 @@ works on its own, and on a [Runic Gateway](https://gitea.whitlocktech.com/RunicG
 website authors its NPC profiles and events use its NPCs. The plan of record, stage by stage, is
 [`docs/runicnpc/PLAN.md`](https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/runicnpc/PLAN.md).
 
-> **Status: stage 0.** The plugin loads, answers its API version, and reports on itself. It spawns
-> nothing yet. Stage 1 is a measuring spike; the NPC and its API arrive in stage 2.
+> **Status: stage 2.** The NPC, its profiles, placements and routes, and the API other plugins call.
+> The in-game `/rnpc` commands arrive in stage 3; until then profiles are edited in
+> `data/RunicNPC/profiles.json` (then `rnpc.reload`), and placements and routes are made through the API.
 
 ## Requirements
 
@@ -53,9 +54,10 @@ Every call is prefixed `RunicNpc_` and reached through `Call`:
 int api = RunicNPC?.Call<int>("RunicNpc_ApiVersion") ?? 0;
 ```
 
-Stage 0 has only `RunicNpc_ApiVersion()`. The full API is planned in PLAN.md §4 and will be
-documented as `docs/runicnpc/API.md` in stage 2. The API version moves when a call or a raised hook
-changes shape, not on every release.
+The API is version 2, documented in
+[`docs/runicnpc/API.md`](https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/runicnpc/API.md):
+spawning and removing NPCs by owner, profiles, placements, routes, the cost warning, and the hooks it raises.
+The API version moves when a call or a raised hook changes shape, not on every release.
 
 ## Repository layout
 
@@ -64,7 +66,22 @@ changes shape, not on every release.
 | `plugin/RunicNPC.cs` | The plugin. The only file a server gets. |
 | `plugin.toml` | Its declarations: API version, framework floors, required plugins. The release copies them into the manifest. |
 | `scripts/checkPlugin.js` | The static checks run on every pull request and again before a release (see its header). |
-| `tools/` | Developer scaffolding for the test rigs, never shipped: the panel scripts (see `tools/rigs.example.json`) and `RunicNpcHarness.cs`, the stage 1 measurement plugin (`docs/runicnpc/PLAN.md` §9). |
+| `tools/` | Developer scaffolding for the test rigs, never shipped: the panel scripts (see `tools/rigs.example.json`); `RunicNpcHarness.cs`, the stage 1 measurement plugin; `RunicNpcTest.cs`, the stage 2 test harness (`rnt.run all`, then `rnt.after` after a reload or restart); and `fieldlist/` with `managed.js`, which regenerate the swap's field list (below). |
+
+## After a Rust update: the swap's field list
+
+Our NPC is Rust's scientist with two components swapped, and the swap copies a fixed list of fields (D232),
+generated from Rust's unmodified assembly. `rnpc.status` reports it as `swap fields: npc=64/64 brain=32/32
+missing=- added=-`. On Carbon, where the assembly is unmodified, `added` names any field Rust has added since
+the list was made. To regenerate it:
+
+```bash
+node tools/managed.js carbon <dir>                         # the Carbon rig's RustDedicated_Data/Managed
+dotnet run --project tools/fieldlist -- <dir>              # rewrites the block in plugin/RunicNPC.cs
+```
+
+Use the Carbon rig: Oxide's patcher makes Rust's private fields public, so its assembly no longer says which
+fields Rust itself serialises.
 
 ## Releases