Initial commit: Triple-C app, container, and CI

Tauri v2 desktop app (React/TypeScript + Rust) for managing
containerized Claude Code environments. Includes Gitea Actions
workflow for building and pushing the sandbox container image,
and a BUILDING.md guide for manual app builds on Linux and Windows.

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

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

@@ -0,0 +1,38 @@
+const SERVICE_NAME: &str = "triple-c";
+const API_KEY_USER: &str = "anthropic-api-key";
+
+pub fn store_api_key(key: &str) -> Result<(), String> {
+    let entry = keyring::Entry::new(SERVICE_NAME, API_KEY_USER)
+        .map_err(|e| format!("Keyring error: {}", e))?;
+    entry
+        .set_password(key)
+        .map_err(|e| format!("Failed to store API key: {}", e))
+}
+
+pub fn get_api_key() -> Result<Option<String>, String> {
+    let entry = keyring::Entry::new(SERVICE_NAME, API_KEY_USER)
+        .map_err(|e| format!("Keyring error: {}", e))?;
+    match entry.get_password() {
+        Ok(key) => Ok(Some(key)),
+        Err(keyring::Error::NoEntry) => Ok(None),
+        Err(e) => Err(format!("Failed to retrieve API key: {}", e)),
+    }
+}
+
+pub fn delete_api_key() -> Result<(), String> {
+    let entry = keyring::Entry::new(SERVICE_NAME, API_KEY_USER)
+        .map_err(|e| format!("Keyring error: {}", e))?;
+    match entry.delete_credential() {
+        Ok(()) => Ok(()),
+        Err(keyring::Error::NoEntry) => Ok(()),
+        Err(e) => Err(format!("Failed to delete API key: {}", e)),
+    }
+}
+
+pub fn has_api_key() -> Result<bool, String> {
+    match get_api_key() {
+        Ok(Some(_)) => Ok(true),
+        Ok(None) => Ok(false),
+        Err(e) => Err(e),
+    }
+}