feat(ui): open DM from filled Favourites tile

Enter on a populated slot of the Favourites grid now jumps straight into
that contact's DM history — resolves the pinned 6-byte pub_key prefix
against the contact list, then routes through new
UITask::openContactDM(ci) which resets QuickMsgScreen and calls
enterDM() to land directly in DM_HIST.

Empty slots still show the "pin from contact options" hint until phase 3
wires the in-grid mini-picker.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/ui-new/QuickMsgScreen.h

@@ -473,6 +473,18 @@ public:
     _viewing_max_seen = 0;
   }
 
+  // Jump straight into a contact's DM history (used by the Favourites dial).
+  // Caller must have already reset() the screen.
+  void enterDM(const ContactInfo& ci) {
+    _sel_contact = ci;
+    _task->clearDMUnread(ci.id.pub_key);
+    _dm_hist_sel = -1;
+    _dm_hist_scroll = 0;
+    _dm_fs.active = false;
+    _room_mode = false;
+    _phase = DM_HIST;
+  }
+
   int render(DisplayDriver& display) override {
     display.setTextSize(1);
     display.setColor(DisplayDriver::LIGHT);

examples/companion_radio/ui-new/UITask.cpp

@@ -860,8 +860,27 @@ public:
       if (c == KEY_UP    && row > 0)                            { _fav_sel -= cols; return true; }
       if (c == KEY_DOWN  && row < rows - 1)                     { _fav_sel += cols; return true; }
       if (c == KEY_ENTER) {
-        // Phase 2/3 wires this: open DM if filled, picker if empty. Consume for now.
+        // Filled slot → open the DM directly. Empty slot waits for phase 3
-        _task->showAlert("Pin from contact options", 1000);
+        // (mini-picker); for now show the pin hint.
+        NodePrefs* p = _task->getNodePrefs();
+        const uint8_t* pfx = (p && _fav_sel < NodePrefs::FAVOURITES_COUNT)
+                             ? p->favourite_contacts[_fav_sel] : nullptr;
+        bool filled = false;
+        if (pfx) for (uint8_t b = 0; b < NodePrefs::FAVOURITE_PREFIX_LEN; b++)
+          if (pfx[b]) { filled = true; break; }
+        if (filled) {
+          for (int idx = 0; ; idx++) {
+            ContactInfo c2;
+            if (!the_mesh.getContactByIdx(idx, c2)) break;
+            if (memcmp(c2.id.pub_key, pfx, NodePrefs::FAVOURITE_PREFIX_LEN) == 0) {
+              _task->openContactDM(c2);
+              return true;
+            }
+          }
+          _task->showAlert("Contact not found", 800);
+        } else {
+          _task->showAlert("Pin from contact options", 1000);
+        }
         return true;
       }
       // Edge LEFT/RIGHT and unhandled keys fall through to page nav below.
@@ -1046,6 +1065,12 @@ void UITask::gotoQuickMsgScreen() {
   setCurrScreen(quick_msg);
 }
 
+void UITask::openContactDM(const ContactInfo& ci) {
+  ((QuickMsgScreen*)quick_msg)->reset();
+  ((QuickMsgScreen*)quick_msg)->enterDM(ci);
+  setCurrScreen(quick_msg);
+}
+
 void UITask::addChannelMsg(uint8_t channel_idx, const char* text) {
   _last_notif_ch_idx = (int)channel_idx;
   ((QuickMsgScreen*)quick_msg)->addChannelMsg(channel_idx, text);

examples/companion_radio/ui-new/UITask.h

@@ -108,6 +108,7 @@ public:
   void gotoHomeScreen() { setCurrScreen(home); }
   void gotoSettingsScreen();
   void gotoQuickMsgScreen();
+  void openContactDM(const ContactInfo& ci);
   void gotoToolsScreen();
   void gotoRingtoneEditor(int slot = 0);
   void gotoBotScreen();