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Excluded from rename: .claude/, devlog/, manascore/ (historical content),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

scripts/mac-mini/launchd/README.md

@@ -32,17 +32,17 @@ for f in *.plist; do launchctl load ~/Library/LaunchAgents/$f; done
 
 ```bash
 # Check status
-launchctl list | grep manacore
+launchctl list | grep mana
 
 # View logs
-tail -f /tmp/manacore-*.log
+tail -f /tmp/mana-*.log
 
 # Reload a service
-launchctl unload ~/Library/LaunchAgents/com.manacore.health-check.plist
-launchctl load ~/Library/LaunchAgents/com.manacore.health-check.plist
+launchctl unload ~/Library/LaunchAgents/com.mana.health-check.plist
+launchctl load ~/Library/LaunchAgents/com.mana.health-check.plist
 
 # Stop a service
-launchctl unload ~/Library/LaunchAgents/com.manacore.<service>.plist
+launchctl unload ~/Library/LaunchAgents/com.mana.<service>.plist
 ```
 
 ## Troubleshooting
@@ -55,5 +55,5 @@ Exit codes in `launchctl list`:
 
 Check error logs:
 ```bash
-cat /tmp/manacore-<service>.error.log
+cat /tmp/mana-<service>.error.log
 ```