fix(rust): protocol 13 — a configuration save that settles after its reload (F9, D179)

The plugin now answers a save once the files are written, with pending and
a writeId, and reports the reload later as a config.outcome event. The save
is recorded as reloading with a settle_by of two plugin ceilings plus slack
on the database's clock; ingest settles the row by (server, writeId), only
while it is still reloading, so a replay moves nothing and a late outcome
still lands. A row past settle_by reads as lost.

GET /admin/rust/config/:serverId/writes/:writeId serves the poll; the page
polls it every two seconds, holds the Save button while it waits, and says
whether a rolled-back plugin came back on its old file. config.outcome is
a staff kind: it carries the server's log tail.

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

server/router/admin/config.router.js

@@ -67,8 +67,8 @@ configRouter.post(
   '/:serverId/file',
   // #swagger.tags = ['Admin · Rust']
   // #swagger.summary = 'Save a configuration file and reload its plugin'
-  // #swagger.description = 'Send `edits` (the generated form: pointers and literals, type-preserving) or `text` (the raw tier: the whole document). `version` must match what the host holds or the save is refused 409 with the current file. The game backs the file up, writes it, reloads the named plugin, and **restores the old file automatically** if the plugin does not come back — which is answered 200 with `report.rolledBack`, because a rollback is a round trip that worked and an edit that did not.'
-  /* #swagger.responses[200] = { description: 'What happened: applied, or rolled back with the reason' } */
+  // #swagger.description = 'Send `edits` (the generated form: pointers and literals, type-preserving) or `text` (the raw tier: the whole document). `version` must match what the host holds or the save is refused 409 with the current file. The game backs the file up, writes it, reloads the named plugin, and **restores the old file automatically** if the plugin fails to load. With a plugin to reload, the answer comes as soon as the file is written — `pending: true` and `write.id` — and the outcome is read from `GET …/writes/{writeId}` once the reload settles. Without one, the answer is final.'
+  /* #swagger.responses[200] = { description: 'Written and reloading (`pending`, with the write’s id), or the final outcome when nothing was reloaded' } */
   /* #swagger.responses[400] = { description: 'Invalid body, an edit the form may not make, or a locked key' } */
   /* #swagger.responses[409] = { description: 'The file changed on the host since it was read' } */
   /* #swagger.responses[503] = { description: 'The sidecar or the game is unreachable' } */
@@ -105,4 +105,18 @@ configRouter.get(
   config.history,
 )
 
+configRouter.get(
+  '/:serverId/writes/:writeId',
+  // #swagger.tags = ['Admin · Rust']
+  // #swagger.summary = 'One configuration write, while its reload settles'
+  // #swagger.description = 'A save that reloads a plugin answers as soon as the file is written, with `pending: true` and this write’s id; the reload can take longer than a request should, behind a cold compile. Poll this until `outcome` leaves `reloading`: `applied`, or `rolled-back` with the reason, the server’s log, and `restored` (whether the plugin came back on its old file). `lost` means the plugin never reported — it was reloaded, or the link dropped — so re-read the file.'
+  /* #swagger.responses[200] = { description: 'The write and how far it has got' } */
+  /* #swagger.responses[404] = { description: 'No such write on that server' } */
+  requireRole('admin'),
+  param('serverId').matches(SERVER_ID),
+  param('writeId').isInt({ min: 1 }),
+  validate,
+  config.writeStatus,
+)
+
 module.exports = configRouter