refactor(config): remove legacy config reference handling and streamline YAML management

- Deleted legacy config reference handling functions and related migration scripts to simplify the codebase.
- Updated documentation to reflect the removal of legacy YAML paths and configurations.
- Adjusted existing YAML management processes to ensure compatibility with the new mustache-style syntax.
- Removed tests related to legacy config references, focusing on current functionality and ensuring clarity in the testing suite.

packages/server/migrations/20260830000007_http_pages.js

@@ -0,0 +1,63 @@
+const DEFAULT_EMAIL_TEMPLATE = `<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>{{title}}</title>
+</head>
+<body>
+  <h1>{{title}}</h1>
+  {{#message}}
+  <p>{{message}}</p>
+  {{/message}}
+
+  <ul>
+    {{#items}}
+    <li>
+      <a href="{{link}}">{{title}}</a>
+      {{#summary}}<p>{{summary}}</p>{{/summary}}
+    </li>
+    {{/items}}
+  </ul>
+  {{^items}}
+  <p>No items.</p>
+  {{/items}}
+</body>
+</html>
+`;
+
+/**
+ * @param {import("knex").Knex} knex
+ */
+export async function up(knex) {
+  await knex.schema.createTable("http_pages", (t) => {
+    t.text("id").primary();
+    t.text("name").notNullable().unique();
+    t.text("content").notNullable();
+    t.text("mime").notNullable();
+    t.integer("status").notNullable().defaultTo(200);
+    t.text("kind").notNullable().defaultTo("response");
+    t.integer("system").notNullable().defaultTo(0);
+    t.text("created_at").notNullable();
+    t.text("updated_at").notNullable();
+  });
+
+  const now = new Date().toISOString();
+  await knex("http_pages").insert({
+    id: "00000000-0000-4000-8000-000000000001",
+    name: "email-default",
+    content: DEFAULT_EMAIL_TEMPLATE,
+    mime: "html",
+    status: 200,
+    kind: "template",
+    system: 1,
+    created_at: now,
+    updated_at: now,
+  });
+}
+
+/**
+ * @param {import("knex").Knex} knex
+ */
+export async function down(knex) {
+  await knex.schema.dropTableIfExists("http_pages");
+}