Add accounts, presets, live sheet panel and equipment tiles

- Login with registration code, sessions, rate limiting, per-user characters
- Share characters with other users (read-only), admin CLI
- Rules presets with a Presets tab, applied/pending changes with diff in a side sheet
- Equipment as tiles with amounts, starting kit removed
- Rename nav tab to "Character", add "New character" button
- Stop tracking _to_delete/

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HJhXuLD2Z6hv3Wqeq9UL9K

frontend/src/legacy.js

@@ -0,0 +1,16 @@
+// Characters and presets made before accounts existed were protected by secret keys in this browser.
+// After login they are handed over to the account once; the old keys are then removed.
+export async function claimLegacy() {
+  const post = (kind, id, token) =>
+    fetch(`/api/claim/${kind}/${id}`, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ token }) }).catch(() => null)
+  try {
+    const chars = JSON.parse(localStorage.getItem('aw_chars')) || []
+    for (const c of chars) if (c?.id && c?.token) await post('characters', c.id, c.token)
+    localStorage.removeItem('aw_chars')
+  } catch { /* nothing to claim */ }
+  try {
+    const presets = JSON.parse(localStorage.getItem('aw_presets')) || {}
+    for (const [id, token] of Object.entries(presets)) await post('presets', id, token)
+    localStorage.removeItem('aw_presets')
+  } catch { /* nothing to claim */ }
+}