feat(theming): settings-store, nav merge util and radius tokens

Phases 0-2 of docs/website/THEMING_AND_NAV.md. Groundwork only: no admin UI,
no consumer wiring, and an instance that never touches the new settings keys
renders exactly as it does today.

Phase 0 - settings store:
- settingsDb.remove() and DELETE /api/v1/admin/settings/:key, the "reset to
  default" primitive. Defaults for these keys live in BRAND_* env, theme.css
  and the hardcoded NAV arrays, so reset has to delete the row rather than
  store a copy of the default. Allowlisted to the five theming/nav keys plus
  hero_layout_draft, admin-only, idempotent.
- GET /api/v1/settings/nav behind requireAuth with no role gate. AdminLayout
  renders for editors and moderators and PlayerPortalLayout for players, and
  none of them can read GET /admin/settings, so without this their nav
  override would silently never apply.
- A fifth router group for it: /public is anonymous, /admin/settings is
  adminOnly, /player is self-scoped data. This is configuration that needs a
  login.
- parseJsonSetting() in utils/settingsJson.js. settings.value is TEXT, so
  every JSON key arrives as a string; malformed or wrong-shaped reads as
  absent, never as an error and never half-applied.
- theme_visual / brand_assets / nav_public join PUBLIC_KEYS; nav_admin and
  nav_player deliberately do not.

Phase 1 - client/src/lib/navOverrides.js, the pure merge util. Presentation
only: it can set label/order/hidden and (grouped navs) group, and nothing
else. It cannot introduce a `to`, cannot touch roles/feature, and hidden:false
cannot un-hide anything - the existing filters run afterward, unchanged, and
remain the boundary.

Phase 2 - promoted 23 border-radius literals in theme.css to four tokens at
today's values (14x8px, 4x999px, 4x10px, 1x12px). The 7px/6px editor chrome
and the two 50% circles stay literal. --shadow-card and --panel-grad were
already tokens.

Tests: 16 new server tests, 20 new client tests. The route-manifest guard now
also asserts /settings/** sits behind requireAuth. Swagger and both route
artifacts regenerated.

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

client/src/lib/navOverrides.js

@@ -0,0 +1,138 @@
+// Apply an admin's stored navigation overrides to a hardcoded NAV array.
+//
+// The three navs (public header, admin sidebar, player portal) stay declared in
+// code; this layer only reorders, relabels and hides what is already there.
+// See docs/website/THEMING_AND_NAV.md §7.
+//
+// **This is presentation, never authorization.** The override can carry
+// `label`, `order`, `hidden` and — admin nav only — `group`, and nothing else.
+// It cannot introduce a `to`, and it cannot touch `roles`, `feature`, `icon` or
+// `end`, so the existing role/feature filters in SiteHeader and AdminLayout run
+// *after* this merge, unchanged, and remain the actual boundary. An override
+// saying `hidden: false` on a role-gated item still shows nothing to a viewer
+// whose role check fails: hiding is subtractive here, never additive.
+//
+// Fail-safe throughout: anything unrecognized — an unknown `to`, a non-string
+// label, a group that does not exist — is ignored rather than rejected, so a
+// stale or hand-edited settings row degrades to the code default instead of
+// rendering a broken nav.
+
+// Two shapes are supported, because two exist:
+//   flat    [{ to, label, ... }]                      — public header, player portal
+//   grouped [{ title?, items: [{ to, label, ... }] }] — admin sidebar
+function isGrouped(nav) {
+  return nav.length > 0 && nav.every((g) => g && Array.isArray(g.items))
+}
+
+// A stored override entry is usable only field by field: a bad `label` must not
+// discard a good `order` alongside it.
+function cleanEntry(raw, groupTitles) {
+  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return null
+  const out = {}
+  if (typeof raw.label === 'string' && raw.label.trim()) out.label = raw.label.trim()
+  if (typeof raw.order === 'number' && Number.isFinite(raw.order)) out.order = raw.order
+  if (raw.hidden === true) out.hidden = true
+  // `group` may only name a section the base nav already declares. Anything else
+  // — a renamed group, a typo, an invented category — is dropped, so an item can
+  // never land in a header that does not exist.
+  if (typeof raw.group === 'string' && groupTitles.has(raw.group)) out.group = raw.group
+  return out
+}
+
+// Sort by effective order, where an item the admin never reordered keeps its
+// index in the base array as its key. Two tie-breaks, in order: an explicit
+// order beats a coincidental index (the admin said "first", so first), and two
+// explicit orders stay in code order (the sort is stable).
+//
+// In practice the editor writes an order for every item in a list, the way
+// drag-and-drop reordering does, so ties are the stale-row case rather than the
+// normal one. They still have to resolve predictably.
+function byOrder(items) {
+  return items
+    .map((item, index) => ({ item, key: item.__order ?? index, explicit: item.__order !== undefined }))
+    .sort((a, b) => a.key - b.key || Number(b.explicit) - Number(a.explicit))
+    .map(({ item }) => {
+      const { __order, ...rest } = item
+      return rest
+    })
+}
+
+// Apply label/hidden/order to one flat list. Returns visible items only, with
+// the sort key parked on `__order` for byOrder to consume.
+function mergeItems(items, entries) {
+  const out = []
+  for (const item of items) {
+    const o = entries.get(item.to)
+    if (o?.hidden) continue
+    // Spread the base item first so `to`, `roles`, `feature`, `icon` and `end`
+    // survive verbatim — the override only ever lands on `label`.
+    out.push({ ...item, ...(o?.label ? { label: o.label } : {}), __order: o?.order })
+  }
+  return out
+}
+
+/**
+ * @param {Array} baseNav  the hardcoded nav — the source of truth for `to`,
+ *   `roles`, `feature`, `icon` and `end`
+ * @param {object|null} overrides  the parsed settings JSON, keyed by `to`, or
+ *   null when the admin never touched this nav
+ * @returns {Array} a new array of the same shape, or `baseNav` itself when there
+ *   is nothing to apply
+ */
+export function applyNavOverrides(baseNav, overrides) {
+  if (!Array.isArray(baseNav)) return []
+  // The untouched path, and the one that matters most: no row, a malformed row,
+  // or a row with nothing usable in it all render the nav exactly as coded.
+  if (!overrides || typeof overrides !== 'object' || Array.isArray(overrides)) return baseNav
+
+  const grouped = isGrouped(baseNav)
+  const groupTitles = new Set(
+    grouped ? baseNav.map((g) => g.title).filter((t) => typeof t === 'string') : [],
+  )
+
+  // Keyed by `to`, and only for a `to` the base nav actually declares. An
+  // override for a route that no longer exists is dropped here, so deleting a
+  // route in code can never leave a dangling override that does something
+  // unexpected later.
+  const known = new Set(
+    grouped ? baseNav.flatMap((g) => g.items.map((i) => i.to)) : baseNav.map((i) => i.to),
+  )
+  const entries = new Map()
+  for (const [to, raw] of Object.entries(overrides)) {
+    if (!known.has(to)) continue
+    const entry = cleanEntry(raw, groupTitles)
+    if (entry && Object.keys(entry).length > 0) entries.set(to, entry)
+  }
+  if (entries.size === 0) return baseNav
+
+  if (!grouped) return byOrder(mergeItems(baseNav, entries))
+
+  // Grouped: an item may also be moved into another *existing* titled section.
+  // Groups keep their coded order — only membership and within-group order move.
+  const moved = new Map() // destination title → items pulled in from elsewhere
+  const kept = baseNav.map((g) => {
+    const items = []
+    for (const item of g.items) {
+      const o = entries.get(item.to)
+      if (o?.group && o.group !== g.title) {
+        if (!moved.has(o.group)) moved.set(o.group, [])
+        moved.get(o.group).push(item)
+        continue
+      }
+      items.push(item)
+    }
+    return { ...g, items }
+  })
+
+  return kept
+    .map((g) => ({
+      ...g,
+      items: byOrder(mergeItems([...g.items, ...(moved.get(g.title) || [])], entries)),
+    }))
+    // A group whose every item was hidden must not leave an orphaned header.
+    // AdminLayout drops empty groups again after its own role filter; doing it
+    // here too keeps the util correct on its own.
+    .filter((g) => g.items.length > 0)
+}
+
+export default applyNavOverrides