Moments: per-user saved pages and regions with one category (BL-0055)

Reader: bookmark button and M save the page (Flow: page at the reading
line, Book: the spread) with an optional dragged region, exactly one
category (Twist, Hot, Awesome, Cute, Funny, Feels) and a note. I now
toggles the bars; ? lists all keys. Keys dispatch through public/keys.js,
which also feeds the new Settings -> Keyboard shortcuts section.

Manga page: "Your moments" strip of crops (story or recent order,
category filters), viewer with step, full page, edit, delete and
"Open in reader" (read.html ...&p=). Moments point at pages by file
name and show "page moved" when the file is gone. Private per user.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

public/manga.html

@@ -9,6 +9,8 @@
 <link rel="manifest" href="manifest.webmanifest">
 <meta name="theme-color" content="#121214">
 <script src="common.js" defer></script>
+<script src="keys.js" defer></script>
+<script src="moments.js" defer></script>
 <script src="manga.js" defer></script>
 </head>
 <body>