feat: TASK-005 - globals.css design tokens

- Added Source Serif 4 font import
- Added new design tokens per strategy spec:
  --bg-void, --bg-panel, --bg-raised (background depth levels)
  --mana-raw, --mana-transference (new mana element colors)
  --border-accent (border highlight)
  --font-display, --font-ui (new font custom properties)
- Replaced hardcoded font-family refs with CSS variables
- Removed redundant .dark block (identical to :root, always dark mode)
- Consolidated @theme inline section to essential mappings

docs/project-structure.txt

@@ -12,11 +12,16 @@ Mana-Loop/
 ├── db/
 │   └── custom.db
 ├── docs/
+│   ├── .workflow/
+│   │   └── TASK-001-playwright-setup.json
 │   ├── strategy/
 │   │   └── overall-remediation-plan.md
 │   ├── tasks/
-│   │   └── TASK-001-playwright-setup.md
+│   │   ├── TASK-001-playwright-setup.md
+│   │   ├── TASK-005-globals-css-tokens.md
+│   │   └── TASK-006-left-panel-redesign.md
 │   ├── GAME_BRIEFING.md
+│   ├── active-task-log.md
 │   ├── circular-deps.txt
 │   ├── dependency-graph.json
 │   ├── project-structure.txt