chore: initial project scaffold

Set up Mangalord with a Rust/axum backend, SvelteKit frontend, Postgres,
and Docker Compose deployment. Establishes the architecture and TDD
patterns the project will extend:

- Hexagonal-ish backend layering (domain / repo / storage / api) with
  a pluggable Storage trait (LocalStorage today, S3 as a future impl).
- Initial migration: users, mangas, chapters, bookmarks.
- Vertical slice for mangas (list, search, create, get) with
  #[sqlx::test] integration coverage and storage unit tests.
- SvelteKit frontend using Svelte 5 runes, typed API client, Vitest
  unit tests and Playwright e2e with route mocking.
- CLAUDE.md documenting layering, TDD/git/SemVer workflow rules, and
  extension points (tags, fulltext search, OCR, S3, auth).
- Project-scoped .claude/settings.json with permission allowlist for
  the toolchain (git, cargo, npm/vite, docker, psql, gh, doc fetches).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/routes/+layout.svelte

@@ -0,0 +1,30 @@
+<script lang="ts">
+    let { children } = $props();
+</script>
+
+<header>
+    <nav>
+        <a href="/">Mangalord</a>
+        <a href="/upload">Upload</a>
+        <a href="/bookmarks">Bookmarks</a>
+    </nav>
+</header>
+
+<main>
+    {@render children()}
+</main>
+
+<style>
+    header {
+        padding: 1rem;
+        border-bottom: 1px solid #ddd;
+    }
+    nav a {
+        margin-right: 1rem;
+    }
+    main {
+        padding: 1rem;
+        max-width: 64rem;
+        margin: 0 auto;
+    }
+</style>