feat(assets): creature artwork from the shard's own client (Phase 3)

Until now the only way a creature got a picture on this site was for an
operator to open UOFiddler on a desktop, export sprites by hand, copy them to
the web host and write a spawnAtlas.art.json naming each one. Almost nobody
did, so shard_spawn_creatures.art was NULL on every install.

The shard has had those files the whole time. Admin -> Shard -> Import now
walks its asset manifest, fetches only the sprites whose hash changed, writes
them under uploads/atlas/, asks the shard for a body id per atlas creature
(§8: it CONSTRUCTS the creature and reads Body.BodyID, which is the only thing
that is right for a shard's own custom creatures) and points each creature at
its picture. On a stock client that is 787 portraits, about a megabyte.

**The one thing v8.md §12 got wrong, and it is not cosmetic.** It says
`shard_spawn_creatures.art` "starts being filled by the import". That table is
emptied and refilled by replaceAtlas on EVERY atlas refresh, and a refresh runs
on every boot -- so a filename stored there would be destroyed by an ordinary
re-parse of the ServUO tree, with the next Update finding the client files
unchanged, reporting "nothing to do", and never restoring it. Nothing would
report a fault; the pictures would just be gone.

So the assets and the body map live in their own tables outside that blast
radius, and applyAtlas re-derives `art` on the way past as
`{ ...derived, ...operatorMap }` -- which is also the one place "the operator's
own artwork wins" is enforced, on every rebuild rather than only at import.

Smaller decisions worth not rediscovering:

- The derivation joins on the catalogue KEY, not on the body id. The simpler
  join is correct today and stops being correct the moment phase 6 adds
  body/400/a2/f0, at which point one slug matches dozens of rows.
- Filenames are content-addressed. A stable name overwritten in place leaves
  every browser and CDN serving the previous client's sprite, with the database
  row perfectly correct.
- An unchanged key whose FILE is missing is fetched again. The row and the disk
  can disagree (a wiped uploads volume, a restore from a dump), and a broken
  image on a creature page is worse than one re-fetched sprite.
- A key the shard cannot render is not a failure. Two thirds of the playable
  ghost and gargoyle bodies have no art on a stock client, and an import that
  reported eight failures every time would teach an operator to ignore the panel.
- A key that VANISHED from the manifest needs review before anything changes:
  an unmounted client volume and a deliberate downgrade look identical here.

23 new tests; 674 server and 42 client tests pass. The SQL was also run against
a real MariaDB, which is what proved the CONCAT join and the singleton CHECK.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4

server/router/admin/shard.router.js

@@ -28,6 +28,7 @@ const shardOps = require('./shardOps.controller')
 const shardVisibility = require('./shardVisibility.controller')
 const shardAtlas = require('./shardAtlas.controller')
 const shardClilocs = require('./shardClilocs.controller')
+const shardAssets = require('./shardAssets.controller')
 const selfShard = require('../player/shard.controller')
 const { requireRole, validate } = core.middleware
 
@@ -362,6 +363,42 @@ shardRouter.put(
   shardClilocs.setPath,
 )
 
+// ── Client assets (admin only) ────────────────────────────────────────────
+// Creature artwork, read from the shard's own UO client over the bridge
+// (docs/link/v8.md §6, §8). Sits beside the cliloc routes for the same reason
+// they sit beside the atlas: static content derived from the operator's own
+// files, and operating it is shard administration.
+//
+// There is deliberately NO public counterpart. The pictures are served as
+// ordinary files under `/uploads`, and `shard_spawn_creatures.art` names them on
+// the atlas responses the site already returns — so nothing public needs to know
+// this pipeline exists.
+shardRouter.get(
+  '/assets',
+  // #swagger.tags = ['Admin · Shard']
+  // #swagger.summary = 'Client asset import status: what is loaded, what the shard has, whether they differ (admin only)'
+  // #swagger.description = 'What the site currently holds (the imported body catalogue, how many sprites are stored, how many atlas creatures resolved to a body id) beside what the shard reports for the client files those pictures come from. `drift: true` means the client files have changed since the last import — press Import. `shard.hashing: true` means a null hash is “not computed yet”, not “changed”: the shard hashes 195 MB anim files off the request path. `shard.imaging.ok: false` is the named NO_IMAGING state — a Linux shard host without libgdiplus cannot render a sprite at all, and the reason names the package to install. A shard with no link configured, or one that is down, is a reported state with a reason rather than an error.'
+  // #swagger.security = [{ "cookieAuth": [] }, { "bearerAuth": [] }]
+  /* #swagger.responses[200] = { description: 'Asset import status', content: { "application/json": { schema: { $ref: "#/components/schemas/UoAssetStatus" } } } } */
+  /* #swagger.responses[403] = { description: 'Admin role required', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  adminOnly,
+  shardAssets.getStatus,
+)
+shardRouter.post(
+  '/assets/import',
+  // #swagger.tags = ['Admin · Shard']
+  // #swagger.summary = 'Import creature artwork from the shard’s UO client (admin only)'
+  // #swagger.description = 'Walks the shard’s asset manifest, fetches only the sprites whose hash changed, stores them under uploads/atlas/, re-resolves every atlas creature to a body id and points each creature at its picture. This is the ONLY thing that imports — boot deliberately never calls the shard — so it is what an operator presses after patching their client. `force` re-imports even when the client files are unchanged. `approve` accepts a catalogue that no longer offers assets this site holds; refused by default, because an unmounted client volume and a deliberate downgrade are indistinguishable from the server and the wrong guess deletes artwork. An operator-supplied `spawnAtlas.art.json` always wins over an imported sprite. Nothing here throws for an operator-visible problem: a shard that is down, an asset plane switched off, or a host that cannot render images all answer 200 with status "unavailable" and a reason naming what to fix. Assets a client simply does not have are NOT failures — two thirds of the playable ghost and gargoyle bodies have no art on a stock client.'
+  // #swagger.security = [{ "cookieAuth": [] }, { "bearerAuth": [] }]
+  /* #swagger.requestBody = { required: false, content: { "application/json": { schema: { type: "object", properties: { force: { type: "boolean", description: "Import even if the shard’s client files are unchanged." }, approve: { type: "boolean", description: "Accept a catalogue that no longer offers assets this site holds." } } } } } } */
+  /* #swagger.responses[200] = { description: 'What happened', content: { "application/json": { schema: { $ref: "#/components/schemas/UoAssetImportResult" } } } } */
+  adminOnly,
+  body('force').optional().isBoolean(),
+  body('approve').optional().isBoolean(),
+  validate,
+  shardAssets.importAssets,
+)
+
 // ── Feature visibility (admin only) ───────────────────────────────────
 // Who can see which shard surface, and which sensitive fields within it. This
 // decides what ANONYMOUS visitors get, so it sits above the moderator tier.