chore: sync Obsidian state + fix .gitignore gaps

Modified files (Obsidian saved state):
  appearance.json       — CSS snippets enabled (Obsidian confirmed)
  community-plugins.json — Excalidraw + Banners enabled (Obsidian confirmed)
  graph.json            — Obsidian reset on close (expected)
  workspace.json        — welcome.canvas added as first tab by Obsidian
  README.md             — cover GIF header preserved by Obsidian
  welcome.canvas        — user added Cosmic Brain GIF at top

.gitignore additions:
  ????-??-??.md    — daily notes from Calendar plugin (personal)
  Excalidraw/      — user Excalidraw drawings (personal, not vault content)
  Untitled.canvas  — unnamed scratch canvases
  Claude SEO*.gif/png — personal brand assets in vault root

.obsidian/graph.json

@@ -67,6 +67,6 @@
   "repelStrength": 20,
   "linkStrength": 1,
   "linkDistance": 80,
-  "scale": 0.5783849446387722,
+  "scale": 0.40700950846340656,
   "close": false
 }