docs: fix stale image-gen refs, Node prereq, version sync; drop dead icons.svg

- README: image gen is sd-server (cross-platform), not macOS/Ollama;
  Node 23.6+ note for self-checks; prefs store row in the data table.
- plan.md: superseded banners on the Ollama image-gen sections.
- gitea-release.sh: syncs Cargo.toml too; bumped to 0.1.3 to match.
- public/icons.svg: unreferenced — favicon.svg is the icon.

scripts/gitea-release.sh

@@ -43,9 +43,14 @@ node -e '
     if(out===t)throw new Error("version not replaced in "+f);
     fs.writeFileSync(f,out);
   }
+  // Cargo.toml: first top-of-file `version = "x.y.z"` (not the deps below it).
+  {const f="src-tauri/Cargo.toml",t=fs.readFileSync(f,"utf8");
+    const out=t.replace(/^version\s*=\s*"\d+\.\d+\.\d+"/m,`version = "${ver}"`);
+    if(out===t)throw new Error("version not replaced in "+f);
+    fs.writeFileSync(f,out);}
 ' "$VER"
 echo "release $TAG (version files synced)"
-git add package.json src-tauri/tauri.conf.json
+git add package.json src-tauri/tauri.conf.json src-tauri/Cargo.toml
 if ! git diff --cached --quiet; then
   git commit -m "chore: release $TAG" -q
   echo "committed version bump"