Add container registry pull, image source settings, and global AWS config

Support pulling images from registry (default: repo.anhonesthost.net/cybercovellc/triple-c/triple-c-sandbox:latest),
local builds, or custom images via a new settings UI. Add global AWS configuration
(config path auto-detect, profile picker, region) that serves as defaults overridable
per-project for Bedrock auth.

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

app/src-tauri/src/storage/mod.rs

@@ -1,5 +1,7 @@
 pub mod projects_store;
 pub mod secure;
+pub mod settings_store;
 
 pub use projects_store::*;
 pub use secure::*;
+pub use settings_store::*;