Fix API key changes not triggering container recreation

The container was only recreated when the auth mode changed, not when
the API key value itself changed. This meant saving a new key required
a manual container rebuild. Now we store a hash of the API key as a
Docker label and compare it on start, so a key change automatically
recreates the container (preserving the claude config volume).

Also adds a note to the global AWS settings UI that changes require a
container rebuild.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src-tauri/src/commands/project_commands.rs

@@ -169,6 +169,7 @@ pub async fn start_project_container(
             let needs_recreation = docker::container_needs_recreation(
                     &existing_id,
                     &project,
+                    api_key.as_deref(),
                     settings.global_claude_instructions.as_deref(),
                     &settings.global_custom_env_vars,
                 )