feat(website): schema-sidebar cast + Ctrl-O/Esc cast keys

Add a `schema-sidebar` cast that reveals the ADR-0046 sidebar with
Ctrl-O (the only way to show it at 90 cols) and steps through the
Tables and Relationships panels. Teach the generator the CtrlO/Esc
control codes; quote control codes so `^[`/`^]` stay valid YAML.

website/casts-src/casts.mjs

@@ -9,7 +9,7 @@
  *   { wait: ms }                      — pause (shown in the recording)
  *   { type: 'text', after: ms }       — type the text + press Enter, then pause
  *   { type: 'text', enter: false }    — type without pressing Enter
- *   { key: 'Tab'|'Enter'|'CtrlC', after } — press a single named key
+ *   { key: 'Tab'|'Enter'|'CtrlC'|'CtrlO'|'Esc', after } — press a single named key
  *
  * Every cast must end by quitting the app so the driver returns to the shell
  * prompt — use `{ key: 'CtrlC' }` (Ctrl-C → quit), NOT a typed `quit`: Ctrl-C
@@ -19,6 +19,35 @@
 
 /** The shared library narrative, trimmed per cast. */
 export const casts = [
+  {
+    name: 'schema-sidebar',
+    title: 'Bring up the schema sidebar and step through tables and relationships',
+    width: 90,
+    height: 26,
+    typeSpeed: '45ms',
+    steps: [
+      { wait: 1000 },
+      // A small two-table schema with one relationship, so both sidebar
+      // panels have something to show.
+      { type: 'create table authors with pk author_id(serial)', after: 650 },
+      { type: 'add column to authors: name (text)', after: 650 },
+      { type: 'create table books with pk book_id(serial)', after: 650 },
+      { type: 'add column to books: title (text)', after: 650 },
+      { type: 'add column to books: author_id (int)', after: 700 },
+      {
+        type: 'add 1:n relationship as books_author from authors.author_id to books.author_id on delete cascade',
+        after: 1400,
+      },
+      // The sidebar is hidden at 90 cols; Ctrl-O reveals it and focuses the
+      // Tables panel (the [CTRL-O] badge shows the otherwise-invisible key).
+      { key: 'CtrlO', after: 2600 },
+      // Ctrl-O again moves focus to the Relationships panel.
+      { key: 'CtrlO', after: 2800 },
+      // Esc leaves navigation mode — the sidebar re-hides.
+      { key: 'Esc', after: 1300 },
+      { key: 'CtrlC' }, // quit invisibly (Ctrl-C) — cast ends on the last content frame
+    ],
+  },
   {
     name: 'projects',
     title: 'Save a project, start fresh, then load it back',