feat: add landing page at / with navigation links

Route GET / to a landing page with the Porchlight logo, tagline,
and card-style navigation links to My Account and Administration.

src/porchlight/app.py

@@ -146,4 +146,8 @@ def create_app(settings: Settings | None = None) -> FastAPI:
     async def health() -> dict[str, str]:
         return {"status": "ok"}
 
+    @app.get("/")
+    async def landing(request: Request):  # type: ignore[no-untyped-def]
+        return templates.TemplateResponse(request, "index.html")
+
     return app

src/porchlight/static/style.css

@@ -530,6 +530,66 @@ li {
     border: 0;
 }
 
+/* ---------- Landing page ---------- */
+
+.landing {
+    text-align: center;
+    padding-top: var(--sp-8);
+}
+
+.landing-logo {
+    width: 6rem;
+    height: 6rem;
+    margin-bottom: var(--sp-6);
+}
+
+.landing h1 {
+    margin-bottom: var(--sp-3);
+}
+
+.landing-blurb {
+    color: var(--fg-muted);
+    font-size: var(--font-size-lg);
+    max-width: 30rem;
+    margin: 0 auto var(--sp-8);
+}
+
+.landing-nav {
+    display: flex;
+    flex-direction: column;
+    gap: var(--sp-4);
+    max-width: 24rem;
+    margin: 0 auto;
+}
+
+.landing-link {
+    display: block;
+    background: var(--surface);
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: var(--sp-4) var(--sp-6);
+    text-decoration: none;
+    text-align: left;
+    transition: border-color 0.15s ease;
+}
+
+.landing-link:hover {
+    border-color: var(--accent);
+    color: inherit;
+}
+
+.landing-link strong {
+    display: block;
+    color: var(--fg);
+    font-size: var(--font-size-base);
+    margin-bottom: var(--sp-1);
+}
+
+.landing-link span {
+    color: var(--fg-muted);
+    font-size: var(--font-size-sm);
+}
+
 /* ---------- Reduced motion ---------- */
 
 @media (prefers-reduced-motion: reduce) {

src/porchlight/templates/index.html

@@ -0,0 +1,19 @@
+{% extends "base.html" %}
+
+{% block content %}
+<div class="landing">
+    <img class="landing-logo" src="/static/logo.svg" alt="" width="96" height="96">
+    <h1>Porchlight</h1>
+    <p class="landing-blurb">OpenID Connect Provider with user management. Manage your identity, credentials, and connected applications.</p>
+    <nav class="landing-nav" aria-label="Quick links">
+        <a class="landing-link" href="/manage/profile">
+            <strong>My Account</strong>
+            <span>Manage your profile and credentials</span>
+        </a>
+        <a class="landing-link" href="/admin/users">
+            <strong>Administration</strong>
+            <span>Manage users and settings</span>
+        </a>
+    </nav>
+</div>
+{% endblock %}

tests/test_app.py

@@ -28,6 +28,18 @@ async def test_app_has_repos_on_state(client: AsyncClient) -> None:
     assert isinstance(app.state.magic_link_repo, MagicLinkRepository)
 
 
+async def test_landing_page(client: AsyncClient) -> None:
+    response = await client.get("/")
+    assert response.status_code == 200
+    assert "text/html" in response.headers["content-type"]
+    body = response.text
+    assert "<h1>Porchlight</h1>" in body
+    assert "/manage/profile" in body
+    assert "/admin/users" in body
+    assert "My Account" in body
+    assert "Administration" in body
+
+
 async def test_dependency_functions() -> None:
     from unittest.mock import MagicMock