feedback1d WN: the local-client slug models are an optional overlay; the manifest never depends on the extraction

data/assets.json pointed 灼热源石虫 / 炽焰源石虫 at /assets/local/ files that only exist
where tools/local-extract ran, with no fallback: without the extraction the
asset tests failed, setup re-ran fetch-assets (rewriting the tracked manifest)
and the slugs drew as icon diamonds.

- The web model stays the 源石虫 alias (spine + spineAliasOf). The official
  model is enemies[id].spineLocal: file names in the data/local-assets.json
  group spine/enemy/<id> plus the parsed metadata, from the committed
  tools/assets/local-enemy-spines.json (fetch-assets --local-spines refreshes
  it from the extracted files, read only). The manifest is byte-identical with
  or without the extraction and has no /assets/local/ URL.
- Client: assets.js spineEntry uses spineLocal only when the local manifest
  lists every file (createFieldView awaits assets.local() with the manifest);
  UnitView loads the web model when the local one fails.
- extract.py writes the atlas with size: / pma: true itself (the same text as
  atlas.mjs normalizeAtlas), so the extraction is usable without a fetch pass.
- setup notes when an older extraction lacks the enemy models.

tools/assets/local-enemy-spines.json

@@ -0,0 +1,113 @@
+{
+  "about": "Spine metadata of the enemy models only the local client has (tools/local-extract/extract.py ENEMY_SPINES); data/assets.json enemies[id].spineLocal. Written by node tools/fetch-assets.mjs --local-spines (docs/ASSETS.md \"Enemy aliases\").",
+  "models": {
+    "enemy_1305_mhslim": {
+      "skel": "enemy_1305_mhslim.skel",
+      "atlas": "enemy_1305_mhslim.atlas",
+      "textures": [
+        "enemy_1305_mhslim.png"
+      ],
+      "pma": true,
+      "anims": {
+        "idle": "Idle",
+        "deploy": "Idle",
+        "attack": {
+          "begin": null,
+          "loop": "Attack",
+          "end": null
+        },
+        "attackDown": null,
+        "skill": {
+          "begin": null,
+          "loop": "Attack",
+          "end": null,
+          "via": "attack",
+          "index": 0,
+          "idle": null
+        },
+        "die": "Die",
+        "move": {
+          "begin": null,
+          "loop": "Move",
+          "end": null
+        },
+        "stun": null
+      },
+      "animations": {
+        "Attack": 1,
+        "Default": 0,
+        "Die": 1,
+        "Idle": 2,
+        "Move": 1
+      },
+      "events": [
+        "OnAttack"
+      ],
+      "hits": {
+        "Attack": [
+          0.667
+        ]
+      },
+      "bounds": {
+        "x": -118.121,
+        "y": -1.969,
+        "width": 230,
+        "height": 164
+      }
+    },
+    "enemy_1305_mhslim_2": {
+      "skel": "enemy_1305_mhslim_2.skel",
+      "atlas": "enemy_1305_mhslim_2.atlas",
+      "textures": [
+        "enemy_1305_mhslim_2.png"
+      ],
+      "pma": true,
+      "anims": {
+        "idle": "Idle",
+        "deploy": "Idle",
+        "attack": {
+          "begin": null,
+          "loop": "Attack",
+          "end": null
+        },
+        "attackDown": null,
+        "skill": {
+          "begin": null,
+          "loop": "Attack",
+          "end": null,
+          "via": "attack",
+          "index": 0,
+          "idle": null
+        },
+        "die": "Die",
+        "move": {
+          "begin": null,
+          "loop": "Move",
+          "end": null
+        },
+        "stun": null
+      },
+      "animations": {
+        "Attack": 1,
+        "Default": 0,
+        "Die": 1,
+        "Idle": 2,
+        "Move": 1
+      },
+      "events": [
+        "OnAttack"
+      ],
+      "hits": {
+        "Attack": [
+          0.667
+        ]
+      },
+      "bounds": {
+        "x": -118.121,
+        "y": -1.969,
+        "width": 230,
+        "height": 164
+      }
+    }
+  }
+}