Replace custom code-server (9GB) with upstream LinuxServer image (~1GB)

Drop the custom Dockerfile.code-server that bundled Claude Code CLI,
Python/MkDocs tooling, and build-essential on top of codercom base.
Switch to the already-mirrored linuxserver/code-server image instead.

- Both compose files: use code-server:latest, LinuxServer env vars
  (PUID/PGID/DEFAULT_WORKSPACE), port 8443, /config mount layout
- Nginx configs + templates: proxy to :8443 instead of :8080
- API env default: CODE_SERVER_URL updated to :8443
- build-and-push.sh: remove --include-code-server flag
- upgrade.sh: remove code-server conditional rebuild + registry fallback
- install.sh: add --ignore-pull-failures for optional missing images
- .env.example, CCP templates, bunker-ops template: updated

Bunker Admin

api/src/config/env.ts

@@ -195,7 +195,7 @@ const envSchema = z.object({
   SMS_DEVICE_MONITOR_INTERVAL_MS: z.coerce.number().default(30000),
 
   // Docs / Code Server
-  CODE_SERVER_URL: z.string().default('http://code-server-changemaker:8080'),
+  CODE_SERVER_URL: z.string().default('http://code-server-changemaker:8443'),
   CODE_SERVER_PORT: z.coerce.number().default(8888),
   MKDOCS_PREVIEW_URL: z.string().default('http://mkdocs-changemaker:8000'),
   MKDOCS_PORT: z.coerce.number().default(4003),