SillyTavern world artifacts, versioned in place

Tracked inside SillyTavern's live data directory rather than symlinked out of
it. data/ is a bind mount into the container, so a symlink to a host path
outside that mount resolves inside the container where the target does not
exist -- broken to SillyTavern while looking correct on the host.

The .gitignore is an allowlist, denying everything and re-including named paths,
because this is live application data rather than a curated export. secrets.json
is the reason: empty today because API keys go through LiteLLM with a
placeholder, and it arms itself the moment a key is typed into the UI. This repo
is public. A denylist protects only the paths someone remembered.

Two of the four artifact types are not diffable as stored. Character cards are
PNGs with the card JSON in a tEXt chunk, and personas live inside a 48 KB
settings.json that SillyTavern rewrites on any change. st-export.py extracts
both into _text/ so the reviewable artifact is text, one-way on purpose --
re-embedding JSON into a PNG is where a mistake corrupts authored content.

Stock content is excluded: Seraphina's expression pack is 3.6 MiB of PNG the app
regenerates on startup. The stock lorebook Eldoria.json stays -- 8 KB of
readable JSON is a useful worked example of the format.

_text/personas.json

@@ -0,0 +1,21 @@
+{
+  "persona_description": "",
+  "persona_descriptions": {
+    "1785686029520-EmyWhyte.png": {
+      "depth": 2,
+      "description": "",
+      "lorebook": "",
+      "position": 0,
+      "role": 0,
+      "title": ""
+    },
+    "user-default.png": {
+      "description": "",
+      "position": 0
+    }
+  },
+  "personas": {
+    "1785686029520-EmyWhyte.png": "Emy Whyte",
+    "user-default.png": "Koivisto"
+  }
+}