Doc: update AGENTS.md with details of auto-update functionality.

Author: joseph

Doc/AGENTS.md

@@ -92,6 +92,9 @@ MVP plan.
 
 - `ErrorPage.swift` — Error-page HTML generator (renders Markdown via MudCore)
 
+- `CheckForUpdatesView.swift` — SparkleController (static updater owner),
+  CheckForUpdatesViewModel (KVO observer), and menu button (`#if SPARKLE`)
+
 **App/CLI/ key files:**
 
 - `main.swift` — `mud` CLI: argument parsing, rendering via MudCore, stdout and
@@ -122,6 +125,9 @@ MVP plan.
 
 - `CommandLineSettingsView.swift` — Command Line settings pane
 
+- `UpdateSettingsView.swift` — Updates pane: auto-update radio group, Check
+  Now, release notes link (`#if SPARKLE`)
+
 - `DebuggingSettingsView.swift` — Debugging pane (debug builds only; reset
   preferences)
 
@@ -163,6 +169,22 @@ MVP plan.
 - `Doc/Guides/command-line.md` — Bundled guide: CLI usage for App Store and
   direct distribution builds
 
+**Scripts and CI:**
+
+- `.github/scripts/update-sparkle` — Download Sparkle framework and CLI tools
+  to `Vendor/Sparkle/`
+- `.github/scripts/build-appcast` — Sign DMG and generate single-item
+  `appcast.xml`
+- `.github/scripts/build-release-notes` — Ruby script: extract per-version
+  sections from `Doc/RELEASES.md` and render HTML via Mud CLI
+
+**Doc:**
+
+- `Doc/RELEASES.md` — User-facing release notes (hand-written, per-version
+  sections)
+- `Site/releases/` — Pre-rendered release notes HTML (generated by
+  `build-release-notes`)
+
 **Important** — Make sure to update this section of `Doc/AGENTS.md` if you add
 or remove key files.