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Excluded from rename: .claude/, devlog/, manascore/ (historical content),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

@@ -188,7 +188,7 @@ If you see `database "xxx" does not exist`:
 pnpm setup:db:chat  # or whichever service
 
 # Option 2: Create manually
-PGPASSWORD=devpassword psql -h localhost -U manacore -d postgres -c "CREATE DATABASE chat;"
+PGPASSWORD=devpassword psql -h localhost -U mana -d postgres -c "CREATE DATABASE chat;"
 ```
 
 ### Schema out of date
@@ -277,7 +277,7 @@ Create `apps/newproject/apps/server/` with:
 1. **Add database to Docker init** (`docker/init-db/01-create-databases.sql`):
    ```sql
    CREATE DATABASE IF NOT EXISTS newproject;
-   GRANT ALL PRIVILEGES ON DATABASE newproject TO manacore;
+   GRANT ALL PRIVILEGES ON DATABASE newproject TO mana;
    ```
 
 2. **Add to setup script** (`scripts/setup-databases.sh`):
@@ -290,7 +290,7 @@ Create `apps/newproject/apps/server/` with:
 
 3. **Add DATABASE_URL to `.env.development`**:
    ```env
-   NEWPROJECT_DATABASE_URL=postgresql://manacore:devpassword@localhost:5432/newproject
+   NEWPROJECT_DATABASE_URL=postgresql://mana:devpassword@localhost:5432/newproject
    ```
 
 4. **Update `scripts/generate-env.mjs`** to generate the server `.env` file.