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Excluded from rename: .claude/, devlog/, manascore/ (historical content),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>

apps/docs/astro.config.mjs

@@ -7,9 +7,9 @@ export default defineConfig({
 	site: 'https://docs.mana.how',
 	integrations: [
 		starlight({
-			title: 'Manacore Docs',
+			title: 'Mana Docs',
 			description:
-				'Documentation for the Manacore ecosystem - a multi-app platform with shared infrastructure.',
+				'Documentation for the Mana ecosystem - a multi-app platform with shared infrastructure.',
 			logo: {
 				light: './src/assets/logo-light.svg',
 				dark: './src/assets/logo-dark.svg',