chore: complete ManaCore → Mana rename (docs, go modules, plists, images)

Final cleanup of references missed in previous rename commits:

- Dockerfiles: PUBLIC_MANA_CORE_AUTH_URL → PUBLIC_MANA_AUTH_URL
- Go modules: github.com/manacore/* → github.com/mana/* (7 go.mod files)
- launchd plists: com.manacore.* → com.mana.* (14 files renamed + content)
- Image assets: *_Manacore_AI_Credits* → *_Mana_AI_Credits* (11 files)
- .env.example files: ManaCore brand strings → Mana
- .prettierignore: stale apps/manacore/* paths → apps/mana/*
- Markdown docs (CLAUDE.md, /docs/*): mana-core-auth → mana-auth, etc.

Excluded from rename: .claude/, devlog/, manascore/ (historical content),
client testimonials, blueprints, npm package refs (@mana-core/*).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/architecture/WORKSPACE_ORCHESTRATOR.md

@@ -256,7 +256,7 @@ interface DropHandler {
 #### 4. Deployment-Konfiguration
 
 ```typescript
-// manacore.config.ts
+// mana.config.ts
 export default defineWorkspace({
   // Welche Apps in diesem Build?
   apps: ['calendar', 'todo', 'contacts'],
@@ -389,7 +389,7 @@ CalendarModule.droppable = [{
 ### Szenario 1: Vollversion (SaaS)
 
 ```typescript
-// manacore.config.ts
+// mana.config.ts
 apps: ['calendar', 'todo', 'contacts', 'chat', 'files', 'notes', ...]
 ```