feat: Excalidraw + Banner plugins + ITS CSS snippets

Plugins installed:
  obsidian-excalidraw-plugin
    manifest.json + styles.css tracked in git
    main.js (8MB) excluded from git — downloaded by setup-vault.sh on first run
  obsidian-banners
    manifest.json + main.js + styles.css all tracked (148KB, acceptable)

CSS Snippets (ITS Theme by SlRvb):
  ITS-Dataview-Cards.css  — transforms TABLE queries into visual card grids
    Usage: use backtick-dataview-cards instead of backtick-dataview above query
  ITS-Image-Adjustments.css — fine-grained image sizing in notes
    Usage: caption images with |100 or wrap in image-adjustments callout

Config updates:
  community-plugins.json — added obsidian-excalidraw-plugin, obsidian-banners
  appearance.json        — added ITS-Dataview-Cards + ITS-Image-Adjustments snippets
                           (vault-colors preserved)
  .gitignore             — added excalidraw main.js exclusion rule

setup-vault.sh — step 5: auto-downloads Excalidraw main.js if missing
  curl from GitHub releases/latest, skips if already present

Canvas updates (Obsidian saved state):
  welcome.canvas — user added Cosmic Brain GIF at top
  main.canvas    — user added brand assets to Wiki Pages zone
  Wiki Map.canvas — Obsidian format normalised

bin/setup-vault.sh

@@ -64,13 +64,29 @@ cat > "$OBSIDIAN/app.json" << 'EOF'
 }
 EOF
 
-# ── 4. Write appearance.json (enable CSS snippet) ────────────────────────────
+# ── 4. Write appearance.json (enable CSS snippets) ───────────────────────────
 cat > "$OBSIDIAN/appearance.json" << 'EOF'
 {
-  "enabledCssSnippets": ["vault-colors"]
+  "enabledCssSnippets": [
+    "vault-colors",
+    "ITS-Dataview-Cards",
+    "ITS-Image-Adjustments"
+  ]
 }
 EOF
 
+# ── 5. Download Excalidraw main.js (8MB, not in git) ─────────────────────────
+EXCALIDRAW="$OBSIDIAN/plugins/obsidian-excalidraw-plugin"
+if [ -f "$EXCALIDRAW/manifest.json" ] && [ ! -f "$EXCALIDRAW/main.js" ]; then
+  echo "Downloading Excalidraw main.js (~8MB)..."
+  curl -sS -L \
+    "https://github.com/zsviczian/obsidian-excalidraw-plugin/releases/latest/download/main.js" \
+    -o "$EXCALIDRAW/main.js"
+  echo "✓ Excalidraw main.js downloaded"
+elif [ -f "$EXCALIDRAW/main.js" ]; then
+  echo "✓ Excalidraw main.js already present"
+fi
+
 echo ""
 echo "✓ Setup complete."
 echo ""