feat(PageHead): make page metadata site-aware with auto-derived canonical URLs

Extract pure resolvePageHeadMeta helper that derives title suffix,
canonical URL, and OpenGraph fallbacks from the active site config and
router pathname. PageHead now reads useSite() + useLocation() to
render per-subdomain metadata (e.g. " | Nessa", canonical on
nessa.freno.me) instead of hardcoding " | Michael Freno".

- Always emit a canonical link (explicit override wins; otherwise
  https://<site.domain><pathname>)
- Default og:image to the site ogDefaultImage when not provided
- Add unit tests covering all five sites, canonical derivation, and
  OpenGraph fallback behavior

src/components/PageHead.test.ts

@@ -0,0 +1,157 @@
+/**
+ * Unit tests for `PageHead` site-aware metadata derivation (task 02).
+ *
+ * `resolvePageHeadMeta` is a pure function over (props, site, pathname), so
+ * these tests mirror the acceptance matrix without a DOM / SolidJS router.
+ * The render layer (`PageHead` component) is a thin wrapper over this function.
+ */
+import { describe, it, expect } from "bun:test";
+import {
+  resolvePageHeadMeta,
+  type PageHeadProps
+} from "~/components/page-head-meta";
+import { SITE_CONFIG, type SiteId } from "~/lib/site-context";
+
+const BASE_PROPS: PageHeadProps = {
+  title: "Blog",
+  description: "Technical blog posts about web development."
+};
+
+describe("resolvePageHeadMeta — title suffix per site", () => {
+  const cases: Array<{ id: SiteId; suffix: string }> = [
+    { id: "main", suffix: " | Michael Freno" },
+    { id: "nessa", suffix: " | Nessa" },
+    { id: "lineage", suffix: " | Life and Lineage" },
+    { id: "gaze", suffix: " | Gaze" },
+    { id: "inputhalo", suffix: " | InputHalo" }
+  ];
+
+  for (const { id, suffix } of cases) {
+    it(`${id} → title is "${BASE_PROPS.title}${suffix}"`, () => {
+      const meta = resolvePageHeadMeta(
+        BASE_PROPS,
+        SITE_CONFIG[id],
+        "/blog"
+      );
+      expect(meta.title).toBe(`${BASE_PROPS.title}${suffix}`);
+    });
+  }
+
+  it("main produces 'Home | Michael Freno' for the homepage", () => {
+    const meta = resolvePageHeadMeta(
+      { title: "Home" },
+      SITE_CONFIG.main,
+      "/"
+    );
+    expect(meta.title).toBe("Home | Michael Freno");
+  });
+});
+
+describe("resolvePageHeadMeta — canonical URL derivation", () => {
+  it("main → canonical starts with https://freno.me", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.main, "/");
+    expect(meta.canonical).toBe("https://freno.me/");
+  });
+
+  it("main blog → https://freno.me/blog", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.main, "/blog");
+    expect(meta.canonical).toBe("https://freno.me/blog");
+  });
+
+  it("nessa → canonical starts with https://nessa.freno.me", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.nessa, "/");
+    expect(meta.canonical).toBe("https://nessa.freno.me/");
+  });
+
+  it("nessa /contact → https://nessa.freno.me/contact", () => {
+    const meta = resolvePageHeadMeta(
+      BASE_PROPS,
+      SITE_CONFIG.nessa,
+      "/contact"
+    );
+    expect(meta.canonical).toBe("https://nessa.freno.me/contact");
+  });
+
+  it("lineage → canonical starts with https://lineage.freno.me", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.lineage, "/");
+    expect(meta.canonical.startsWith("https://lineage.freno.me")).toBe(true);
+  });
+
+  it("gaze → canonical starts with https://gaze.freno.me", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.gaze, "/");
+    expect(meta.canonical.startsWith("https://gaze.freno.me")).toBe(true);
+  });
+
+  it("inputhalo → canonical starts with https://inputhalo.freno.me", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.inputhalo, "/");
+    expect(meta.canonical.startsWith("https://inputhalo.freno.me")).toBe(true);
+  });
+
+  it("preserves the full pathname including nested segments + search is NOT included", () => {
+    // useLocation().pathname excludes the query string; canonical should too.
+    const meta = resolvePageHeadMeta(
+      BASE_PROPS,
+      SITE_CONFIG.main,
+      "/blog/my-post"
+    );
+    expect(meta.canonical).toBe("https://freno.me/blog/my-post");
+  });
+
+  it("explicit `canonical` prop overrides auto-derivation", () => {
+    const meta = resolvePageHeadMeta(
+      { ...BASE_PROPS, canonical: "https://example.com/override" },
+      SITE_CONFIG.nessa,
+      "/contact"
+    );
+    expect(meta.canonical).toBe("https://example.com/override");
+  });
+});
+
+describe("resolvePageHeadMeta — OpenGraph fallbacks", () => {
+  it("ogImage defaults to the site's ogDefaultImage when not provided", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.nessa, "/");
+    expect(meta.ogImage).toBe(SITE_CONFIG.nessa.ogDefaultImage);
+  });
+
+  it("explicit ogImage overrides the site default", () => {
+    const meta = resolvePageHeadMeta(
+      { ...BASE_PROPS, ogImage: "https://cdn/custom.png" },
+      SITE_CONFIG.main,
+      "/"
+    );
+    expect(meta.ogImage).toBe("https://cdn/custom.png");
+  });
+
+  it("ogTitle falls back to the base title (no suffix)", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.main, "/");
+    expect(meta.ogTitle).toBe("Blog");
+  });
+
+  it("explicit ogTitle overrides the title fallback", () => {
+    const meta = resolvePageHeadMeta(
+      { ...BASE_PROPS, ogTitle: "Custom OG Title" },
+      SITE_CONFIG.main,
+      "/"
+    );
+    expect(meta.ogTitle).toBe("Custom OG Title");
+  });
+
+  it("ogDescription falls back to description", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.main, "/");
+    expect(meta.ogDescription).toBe(BASE_PROPS.description);
+  });
+
+  it("explicit ogDescription overrides the description fallback", () => {
+    const meta = resolvePageHeadMeta(
+      { ...BASE_PROPS, ogDescription: "Custom OG desc" },
+      SITE_CONFIG.main,
+      "/"
+    );
+    expect(meta.ogDescription).toBe("Custom OG desc");
+  });
+
+  it("description is passed through unchanged", () => {
+    const meta = resolvePageHeadMeta(BASE_PROPS, SITE_CONFIG.main, "/");
+    expect(meta.description).toBe(BASE_PROPS.description);
+  });
+});