v0.2.4 - Hotfix: Unknown status + copy UX + update banner context

Bug fix:
- config.py: empty PARAKEET_CONTAINER / MAGPIE_CONTAINER env vars (from migrating to v0.2.0+ where the field is optional and saved as '') now fall back to 'parakeet-asr' / 'magpie-tts' via the 'or' idiom. Confirmed live: services classify as 'running' instead of 'unknown'.

UX:
- Replaced text 'Copy' buttons with compact icon buttons (clipboard SVG)
- Endpoint Base URL + Model ID + curl snippet are now click-to-copy themselves (the value AND a separate icon button)
- Service cards: host, base URL, and model are now three separate copyable rows
- Update banner: leading explanatory line — 'Updates to eugr/spark-vllm-docker — the upstream project that orchestrates vLLM on your Sparks. These are not firmware, OS, or model updates.' with a link to the repo.

image/app/config.py

@@ -55,10 +55,10 @@ class Settings:
             spark2_user=spark2_user,
             parakeet_host=_env("PARAKEET_HOST") or spark2_host,
             parakeet_user=_env("PARAKEET_USER") or spark2_user,
-            parakeet_container=_env("PARAKEET_CONTAINER", "parakeet-asr"),
+            parakeet_container=_env("PARAKEET_CONTAINER") or "parakeet-asr",
             magpie_host=_env("MAGPIE_HOST") or spark2_host,
             magpie_user=_env("MAGPIE_USER") or spark2_user,
-            magpie_container=_env("MAGPIE_CONTAINER", "magpie-tts"),
+            magpie_container=_env("MAGPIE_CONTAINER") or "magpie-tts",
             ssh_key_path=_env("SSH_KEY_PATH"),
             ssh_known_hosts=_env("SSH_KNOWN_HOSTS"),
             models_yaml=_resolve_models_yaml(),