fix(companion): pack and history files from the card checked, contact loops skip the reserved slots, small UI fixes

- L2 vector packs: a damaged count can't wrap the index size, and an
  entry pointing past the file is refused.
- L2 map share-target list: sized for 40 long channel names and 16
  favourites (it could overflow), off the stack.
- L2 SD history: a file with an unreadable header is set aside as .bad
  instead of written over; Delete message history takes those too.
- Contact lookups by key or hash start after the reserved anon slots (an
  empty one matched a 00 hop hash with a blank name); MessagesScreen uses
  contactctl::hopName().
- Nearby keeps its selection by public key: deleting a contact shifts
  the table.
- ui-new Live Share target cycle holds every channel and favourite.

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

examples/companion_radio/ui-new/HomeScreen.h

@@ -1491,7 +1491,7 @@ public:
             }
           }
         } else if (prefix) {
-          for (int idx = 0; ; idx++) {
+          for (int idx = MAX_ANON_CONTACTS; ; idx++) {
             ContactInfo c;
             if (!the_mesh.getContactByIdx(idx, c)) break;
             if (memcmp(c.id.pub_key, prefix, NodePrefs::FAVOURITE_PREFIX_LEN) == 0) {
@@ -1673,7 +1673,7 @@ public:
           _task->openChannelHistory(pfx[0]);
           return true;
         }
-        for (int idx = 0; ; idx++) {
+        for (int idx = MAX_ANON_CONTACTS; ; idx++) {
           ContactInfo c2;
           if (!the_mesh.getContactByIdx(idx, c2)) break;
           if (memcmp(c2.id.pub_key, pfx, NodePrefs::FAVOURITE_PREFIX_LEN) == 0) {

examples/companion_radio/ui-new/LiveShareScreen.h

@@ -157,14 +157,17 @@ public:
   }
 
   void cycleTarget(int dir) {
-    struct T { uint8_t type, ch; uint8_t prefix[NodePrefs::FAVOURITE_PREFIX_LEN]; } list[24];
+    // Every channel and every dial favourite: a cap under MAX_GROUP_CHANNELS
+    // (40) left the favourites, listed last, out of reach.
+    static const int LIST_MAX = MAX_GROUP_CHANNELS + NodePrefs::FAVOURITES_COUNT;
+    struct T { uint8_t type, ch; uint8_t prefix[NodePrefs::FAVOURITE_PREFIX_LEN]; } list[LIST_MAX];
     int n = 0;
     ChannelDetails ch;
-    for (int i = 0; i < 64 && n < 24; i++) {
+    for (int i = 0; i < MAX_GROUP_CHANNELS && n < LIST_MAX; i++) {
       if (!the_mesh.getChannel(i, ch) || ch.name[0] == '\0') continue;
       list[n].type = 0; list[n].ch = (uint8_t)i; n++;
     }
-    for (int i = 0; i < NodePrefs::FAVOURITES_COUNT && n < 24; i++) {
+    for (int i = 0; i < NodePrefs::FAVOURITES_COUNT && n < LIST_MAX; i++) {
       const uint8_t* pre = _prefs->favourite_contacts[i];
       bool empty = true;
       for (int b = 0; b < NodePrefs::FAVOURITE_PREFIX_LEN; b++) if (pre[b]) { empty = false; break; }

examples/companion_radio/ui-new/LocatorScreen.h

@@ -195,13 +195,13 @@ public:
     none.kind = 2; none.lat = 0; none.lon = 0; none.ts = 0; none.live = false; none.fav = false;
     memset(none.key, 0, 6);
     snprintf(none.name, sizeof(none.name), "(none)");
-    for (int idx = 0; _target_n < TARGET_MAX; idx++) {
+    for (int idx = MAX_ANON_CONTACTS; _target_n < TARGET_MAX; idx++) {
       ContactInfo c;
       if (!the_mesh.getContactByIdx(idx, c)) break;
       if (!contactctl::favourite(c)) continue;
       addPersonTarget(c.id.pub_key, c.name, /*require_position=*/false, true);
     }
-    for (int idx = 0; _target_n < TARGET_MAX; idx++) {
+    for (int idx = MAX_ANON_CONTACTS; _target_n < TARGET_MAX; idx++) {
       ContactInfo c;
       if (!the_mesh.getContactByIdx(idx, c)) break;
       addPersonTarget(c.id.pub_key, c.name, /*require_position=*/true, contactctl::favourite(c));

examples/companion_radio/ui-new/MessagesScreen.h

@@ -383,24 +383,6 @@ class MessagesScreen : public UIScreen {
     }
   }
 
-  // Resolve one hop's path hash to a contact name, falling back to a short hex
-  // tag ("?AABB") when no known contact matches -- an unnamed/unknown repeater,
-  // or one whose contact card has since been removed.
-  void resolveHopName(const uint8_t* hash, uint8_t hash_size, char* out, size_t out_sz) {
-    for (int idx = 0; ; idx++) {
-      ContactInfo c;
-      if (!the_mesh.getContactByIdx(idx, c)) break;
-      if (c.id.isHashMatch(hash, hash_size)) {
-        snprintf(out, out_sz, "%s", c.name);
-        return;
-      }
-    }
-    char hex[9] = {0};
-    uint8_t n = hash_size > 4 ? 4 : hash_size;
-    for (uint8_t b = 0; b < n; b++) snprintf(hex + b * 2, 3, "%02X", hash[b]);
-    snprintf(out, out_sz, "?%s", hex);
-  }
-
   // Opens the path/relay detail popup for the entry stashed by buildFsMenu().
   // Incoming: hops listed oldest-hop-first (the order they were appended as the
   // message travelled). Outgoing channel: each distinct repeater heard echoing
@@ -423,7 +405,7 @@ class MessagesScreen : public UIScreen {
     uint8_t max_hops = MAX_HIST_PATH_BYTES / hash_size;   // matches capturePath()/markChannelRelayed()'s write-side bound
     if (hop_count > max_hops) hop_count = max_hops;
     for (uint8_t i = 0; i < hop_count; i++) {
-      resolveHopName(&path[i * hash_size], hash_size, _path_detail_names[i], sizeof(_path_detail_names[i]));
+      contactctl::hopName(path_len_packed, path, i, _path_detail_names[i], sizeof(_path_detail_names[i]));
     }
     _ctx_menu.begin(path_is_relay ? "Relayed by" : "Path", hop_count);
     for (uint8_t i = 0; i < hop_count; i++) _ctx_menu.addItem(_path_detail_names[i]);
@@ -724,7 +706,7 @@ class MessagesScreen : public UIScreen {
           DisplayDriver::translateUTF8Static(nm + 1, chanctl::bareName(ch.name), sizeof(nm) - 1);
         }
       } else {
-        for (int idx = 0; ; idx++) {
+        for (int idx = MAX_ANON_CONTACTS; ; idx++) {
           ContactInfo c2;
           if (!the_mesh.getContactByIdx(idx, c2)) break;
           if (memcmp(c2.id.pub_key, pfx, NodePrefs::FAVOURITE_PREFIX_LEN) == 0) {

examples/companion_radio/ui-new/NearbyScreen.h

@@ -105,20 +105,22 @@ class NearbyScreen : public UIScreen, protected NearbyModel {
   void refresh()       { refreshModel(); clampSelection(); }
 
   // Rebuild the stored list (re-merge live shares + re-sort) while keeping the
-  // currently highlighted node selected across the rebuild — by contact index
+  // currently highlighted node selected across the rebuild — by public key
   // for a stored node, or by name for a non-contact live sender. Returns false
   // if that node is no longer in the list (caller decides whether to drop the
   // detail/nav view). Shared by the list, detail and navigate refresh paths.
   bool refreshKeepingSelection() {
-    int  saved_idx  = (_sel < _count) ? _entries[_sel].contact_idx : -1;
-    bool saved_live = (_sel < _count) && _entries[_sel].is_live && saved_idx < 0;
+    bool saved_contact = (_sel < _count) && _entries[_sel].contact_idx >= 0;
+    bool saved_live = (_sel < _count) && _entries[_sel].is_live && !saved_contact;
+    uint8_t saved_key[PUB_KEY_SIZE];
+    if (saved_contact) memcpy(saved_key, _entries[_sel].pub_key, PUB_KEY_SIZE);
     char saved_name[sizeof(_entries[0].name)]; saved_name[0] = '\0';
     if (_sel < _count) {
       strncpy(saved_name, _entries[_sel].name, sizeof(saved_name) - 1);
       saved_name[sizeof(saved_name) - 1] = '\0';
     }
     refreshStored();
-    int i = saved_idx >= 0 ? findContact(saved_idx)
+    int i = saved_contact ? findContact(saved_key)
           : (saved_live && saved_name[0]) ? findLiveByName(saved_name) : -1;
     if (i >= 0) { _sel = i; return true; }
     return false;