Parent controls for children, name-tile sign-in, restricted Learn search, simple mode

- Sign-in page shows name tiles on remembered devices; tap a name, then PIN or passkey
- Music and Movies are separate on the server; Plex can be locked to a child's managed profile
- Activity log, weekly summary and alerts to parents; per-area and weekend limits
- Requests from children (Ask button) answered in Settings; bonus screen time from rewards
- Restricted Learn search (Simple English Wikipedia, blocked words) replaces web search for children
- Simple mode (big-button home) for young children or grandparents
- Child usage kept in memory instead of read from disk on every request
- Tests and README updated

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

public/login.html

@@ -49,6 +49,13 @@
   .box img { width: 72px; height: 72px; border-radius: 18px; margin-bottom: 16px; }
   .box .btn { width: 100%; justify-content: center; min-height: 52px; font-size: 17px; }
   .box form { text-align: left; }
+  .box.wide { max-width: 560px; }
+  .tiles { display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; margin: 14px 0; }
+  .tile { display: flex; flex-direction: column; align-items: center; gap: 6px; width: 104px; padding: 12px 6px; border-radius: 18px; background: var(--panel); border: 1px solid var(--line); color: var(--text); cursor: pointer; font: inherit; }
+  .tile:active { transform: scale(.97); } .tile .av { width: 60px; height: 60px; border-radius: 50%; color: #fff; display: grid; place-items: center; font-size: 26px; font-weight: 700; } .tile b { font-size: 16px; } .tile small { min-height: 14px; }
+  .kidtag { background: #2f9e6e; color: #fff; border-radius: 8px; padding: 1px 7px; font-size: 11px; font-weight: 700; }
+  .pad { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; max-width: 300px; margin: 10px auto 0; } .pad button { height: 64px; font-size: 26px; border-radius: 16px; background: var(--panel2); color: var(--text); border: 1px solid var(--line); font-family: inherit; }
+  .dots { display: flex; justify-content: center; gap: 12px; margin: 12px 0; min-height: 18px; } .dots i { width: 16px; height: 16px; border-radius: 50%; background: var(--line); } .dots i.on { background: var(--accent); }
 </style>
 </head>
 <body>