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/hooks/useSettings.ts

@@ -0,0 +1,38 @@
+import { useCallback } from "react";
+import { useAppState } from "../store/appState";
+import * as commands from "../lib/tauri-commands";
+
+export function useSettings() {
+  const { hasKey, setHasKey } = useAppState();
+
+  const checkApiKey = useCallback(async () => {
+    try {
+      const has = await commands.hasApiKey();
+      setHasKey(has);
+      return has;
+    } catch {
+      setHasKey(false);
+      return false;
+    }
+  }, [setHasKey]);
+
+  const saveApiKey = useCallback(
+    async (key: string) => {
+      await commands.setApiKey(key);
+      setHasKey(true);
+    },
+    [setHasKey],
+  );
+
+  const removeApiKey = useCallback(async () => {
+    await commands.deleteApiKey();
+    setHasKey(false);
+  }, [setHasKey]);
+
+  return {
+    hasKey,
+    checkApiKey,
+    saveApiKey,
+    removeApiKey,
+  };
+}