feat: main.canvas as default workspace view

workspace.json — Obsidian saved state with main.canvas as active tab
  - Active leaf: wiki/canvases/main.canvas (opened when vault loads)
  - Contains user's canvas: title card, General zone, Wiki Pages zone
  - Nodes: logo, LLM Wiki Pattern note, insight text card + user additions

workspace-visual.json — updated default tab order
  - Tab 1 (default): wiki/canvases/main.canvas
  - Tab 2: projects/visual-vault/design-ideas.canvas
  - Tab 3: wiki/Wiki Map.canvas
  - Tab 4: Graph view
  - Right sidebar: Calendar + Thino + Backlinks (open)

wiki/canvases/main.canvas — first real canvas with user content
  - General zone: logo-pro.png, LLM Wiki Pattern note, insight text
  - Wiki Pages zone: Cosmic Brain cover + GIFs (user additions)

.gitignore — added patterns for personal files Obsidian drops in root

.gitignore

@@ -29,3 +29,9 @@ node_modules/
 .env
 .env.local
 *.local.md
+
+# Personal files dropped into vault root by Obsidian (don't commit these)
+WIKI*.md
+PROMPT.md
+*.tmp.*
+"Obsidian vault*"