feat(web): blog-post ingestion webhook + /blog, dynamic RSS & sitemap

Add an autoblog webhook receiver and a Supabase-backed blog to logicsrc-web
(the app had no Supabase usage before).

- Migration: blog_posts table (RLS: public reads published, service-role
  writes). Applied to the linked project.
- POST /api/webhooks/blog: verifies the Standard Webhooks signature against
  BLOG_WEBHOOK_SECRET via @profullstack/autoblog verifyAndParse (no admin
  user — shared secret only) and upserts the post by slug.
- /blog index + /blog/[slug] render published posts from the table.
- /blog/rss.xml and /sitemap.xml are now dynamic, generated from the table;
  removed the static public/sitemap.xml and public/blog/rss.xml.
- BLOG_WEBHOOK_SECRET added to .env.example.

Verified end-to-end: a signed sample post delivered 200 and appeared in the
index, post page, RSS, and sitemap; build + typecheck pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/logicsrc-web/src/app/sitemap.ts

@@ -0,0 +1,58 @@
+import type { MetadataRoute } from "next";
+import { publicClient } from "@/lib/supabase";
+
+export const dynamic = "force-dynamic";
+
+function baseUrl(): string {
+  return (process.env.PUBLIC_URL ?? "https://logicsrc.com").replace(/\/$/, "");
+}
+
+// Static routes preserved from the legacy public/sitemap.xml.
+const STATIC_ROUTES: Array<{
+  path: string;
+  changeFrequency: MetadataRoute.Sitemap[number]["changeFrequency"];
+  priority: number;
+}> = [
+  { path: "/", changeFrequency: "weekly", priority: 1.0 },
+  { path: "/docs", changeFrequency: "weekly", priority: 0.9 },
+  { path: "/openspec", changeFrequency: "weekly", priority: 0.8 },
+  { path: "/agent-swarm", changeFrequency: "weekly", priority: 0.8 },
+  { path: "/agentbyte", changeFrequency: "weekly", priority: 0.8 },
+  { path: "/credential-sharing", changeFrequency: "weekly", priority: 0.8 },
+  { path: "/hire-us", changeFrequency: "weekly", priority: 0.8 },
+  { path: "/blog", changeFrequency: "daily", priority: 0.7 },
+  { path: "/about", changeFrequency: "monthly", priority: 0.6 },
+  { path: "/terms", changeFrequency: "monthly", priority: 0.4 },
+  { path: "/privacy", changeFrequency: "monthly", priority: 0.4 },
+];
+
+export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
+  const base = baseUrl();
+
+  const staticEntries: MetadataRoute.Sitemap = STATIC_ROUTES.map((route) => ({
+    url: `${base}${route.path}`,
+    changeFrequency: route.changeFrequency,
+    priority: route.priority,
+  }));
+
+  let postEntries: MetadataRoute.Sitemap = [];
+  try {
+    const supabase = publicClient();
+    const { data } = await supabase
+      .from("blog_posts")
+      .select("slug, published_at, updated_at")
+      .eq("status", "published")
+      .order("published_at", { ascending: false });
+    postEntries = (data ?? []).map((post) => ({
+      url: `${base}/blog/${post.slug}`,
+      lastModified: new Date(post.updated_at ?? post.published_at),
+      changeFrequency: "weekly",
+      priority: 0.6,
+    }));
+  } catch {
+    // If the DB is unreachable, still serve the static sitemap.
+    postEntries = [];
+  }
+
+  return [...staticEntries, ...postEntries];
+}