chore: drop HOST overrides, move known issue to docs, tidy comments and gitignores

- Remove HOST=${SERVICE_HOSTNAME} from code-server, code-server-lsio and paseo; hostname: alone sets the name
- Move SERVICE_HOSTNAME to the top of their .env.example to match compose order
- Drop the openclaw ARM64 Chromium note from its README; docs/openclaw covers it
- List CUSTOM_USER in webtop's setup step
- Trim reasoning from diun and paseo comments
- Delete stale gitea and gitea-mirror .gitignore files
- Add TODO.md for remaining naming and README issues

code-server-lsio/compose.yml

@@ -17,7 +17,6 @@ services:
       - GIT_AUTHOR_EMAIL=${GIT_EMAIL}
       - GIT_COMMITTER_NAME=${GIT_NAME}
       - GIT_COMMITTER_EMAIL=${GIT_EMAIL}
-      - HOST=${SERVICE_HOSTNAME}
       # - PWA_APPNAME=${PWA_APPNAME:-code-server}
     volumes:
       - 'code-server-config:/config'