fix(hotkeys): name the combo another app already owns

Two gaps when Windows refuses a RegisterHotKey:
- the toast said "one or both hotkeys" — wrong since there are three autofill
  combos, and it never said which one lost.
- Quick search and New entry failures were only written to the debug panel,
  which is off in production: the hotkey silently did nothing with no clue why.

Delphi now exposes the per-slot registration outcome and the host accumulates
the failed combo names across all five hotkeys, emitting one notification for
the batch. A combo the user deliberately cleared (vk=0) is never listed.
JS names them: "Already used by another app: 2FA code — pick another combo in
Settings".

Registration stays best-effort per slot: one clash doesn't disarm the others.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

TEST_SCENARIOS.md

@@ -308,6 +308,12 @@ l'éditeur slideover : créer + éditer une entrée, ajouter/retirer des tags,
 - **ACTION** : verrouiller → `Ctrl+Shift+T`.
 - **ATTENDU** : l'app revient au premier plan avec le focus sur le master password (même comportement que les autres hotkeys), pas de no-op silencieux.
 
+### H7 · combo déjà pris par une autre application
+- **ACTION** : assigner à un hotkey un combo qu'une autre app tient déjà en global (ex. `Ctrl+Shift+Q` si Quick Assist / un lanceur l'occupe ; sinon, tester en assignant le même combo dans deux apps).
+- **ATTENDU** : toast **nommant le combo refusé** — « Already used by another app: 2FA code — pick another combo in Settings ». Les **autres** hotkeys restent fonctionnels (enregistrement best-effort, pas de tout-ou-rien).
+- **ACTION 2** : fermer l'app concurrente → *Reset to defaults* (ou re-capturer le combo) → le hotkey redevient actif.
+- **Historique** : le message disait « one or both hotkeys » (faux depuis qu'il y en a 3) sans dire lequel ; et un échec sur **Quick search** ou **New entry** n'était écrit que dans le panel debug — invisible en prod, le hotkey semblait juste cassé.
+
 ### H6 · code en fin de période
 - **ACTION** : presser le hotkey juste avant la fin du compte à rebours de 30 s.
 - **ATTENDU** : le code tapé est celui de la période **courante** au moment de la frappe (généré à la demande, pas mis en cache).

delphi-backend/Source/PM.Bridge.pas

@@ -202,6 +202,12 @@ type
     property SecureClipboard: TSecureClipboard read FSecureClipboard;
     property TrayAdded: Boolean read FTrayAdded;
     property AutofillRegistered: Boolean read FAutofillRegistered;
+    // Per-slot outcome of the last SetAutofillHotkeys — lets the host name
+    // exactly which combo lost the race with another app's global hotkey
+    // instead of a vague "one of them failed".
+    property AutofillFullActive: Boolean read FAutofillFullActive;
+    property AutofillPwdActive:  Boolean read FAutofillPwdActive;
+    property AutofillTotpActive: Boolean read FAutofillTotpActive;
     // Fired on main thread when Windows locks the session (WTS_SESSION_LOCK).
     property OnSystemLock: TProc read FOnSystemLock write FOnSystemLock;
     // True once WM_QUERYENDSESSION (or WM_ENDSESSION) has been received.

delphi-backend/UMainForm.pas

@@ -863,6 +863,11 @@ begin
   // we register both with the supplied combos (replacing any prior).
   else if ACmd = 'autofill/hotkeys' then
   begin
+    // Names of the combos Windows refused (already held by another app), so
+    // the toast can say WHICH one is dead instead of leaving the user to
+    // wonder why a hotkey silently does nothing. A combo the user cleared
+    // (vk=0) is skipped on purpose and never listed here.
+    var LFailed := '';
     // Quick-search combo is set unconditionally (independent of the
     // autofill enabled flag) so the picker stays armed even when the
     // autofill hotkeys are turned off.
@@ -871,6 +876,7 @@ begin
       var LQsMods := Word(StrToIntDef(GetParam('qs_mods'), 6));
       var LQsVk   := Word(StrToIntDef(GetParam('qs_vk'),   Ord('Q')));
       var LQsOk   := FBridge.SetQuickSearchHotkey(LQsMods, LQsVk);
+      if (not LQsOk) and (LQsVk <> 0) then LFailed := LFailed + 'Quick search, ';
       LogLine(Format('Quick-search hotkey set — mods:%d vk:%d (ok=%s)',
         [LQsMods, LQsVk, BoolToStr(LQsOk, True)]));
     end;
@@ -881,6 +887,7 @@ begin
       var LNeMods := Word(StrToIntDef(GetParam('ne_mods'), 6));
       var LNeVk   := Word(StrToIntDef(GetParam('ne_vk'),   Ord('A')));
       var LNeOk   := FBridge.SetNewEntryHotkey(LNeMods, LNeVk);
+      if (not LNeOk) and (LNeVk <> 0) then LFailed := LFailed + 'New entry, ';
       LogLine(Format('New-entry hotkey set — mods:%d vk:%d (ok=%s)',
         [LNeMods, LNeVk, BoolToStr(LNeOk, True)]));
     end;
@@ -903,12 +910,19 @@ begin
                                                   LTotpMods, LTotpVk);
       LogLine(Format('Autofill hotkeys set — full=mods:%d vk:%d  pwd=mods:%d vk:%d  totp=mods:%d vk:%d  (all_ok=%s)',
         [LFullMods, LFullVk, LPwdMods, LPwdVk, LTotpMods, LTotpVk, BoolToStr(LAllOk, True)]));
-      // Notify JS of the result so the UI can flag a failed-to-register combo
+      if (not FBridge.AutofillFullActive) and (LFullVk <> 0) then
-      // (typically a clash with another app's global hotkey).
+        LFailed := LFailed + 'Autofill (full), ';
+      if (not FBridge.AutofillPwdActive) and (LPwdVk <> 0) then
+        LFailed := LFailed + 'Password only, ';
+      if (not FBridge.AutofillTotpActive) and (LTotpVk <> 0) then
+        LFailed := LFailed + '2FA code, ';
+    end;
+    // One notification for the whole batch, naming the combos that failed —
+    // empty string = everything registered.
+    LFailed := LFailed.TrimRight([',', ' ']);
     WebBrowser.ExecuteJavaScript(
       'if(window.Bridge&&Bridge.onAutofillHotkeysResult)' +
-        'Bridge.onAutofillHotkeysResult(' + BoolToStr(LAllOk, True).ToLower + ')');
+      'Bridge.onAutofillHotkeysResult("' + LFailed.Replace('"', '') + '")');
-    end;
   end
 
   // execute: JS has matched an entry, decrypted the password, and is

js/app.js

@@ -218,12 +218,15 @@ const Bridge = (() => {
         // Called by Delphi after a setAutofillHotkeys request, with true if
         // BOTH combos registered successfully, false otherwise (clash with
         // another app holding a global hotkey). Surfaces a toast.
-        onAutofillHotkeysResult(allOk) {
+        // `failed` = comma-separated names of the combos Windows refused
-            if (allOk) {
+        // (another app already owns them); empty string = all registered.
-                toast('Autofill hotkeys updated');
+        // Naming them matters: a clashing hotkey is otherwise indistinguishable
-            } else {
+        // from a broken feature — it just silently does nothing.
-                toast('Autofill: one or both hotkeys are already used by another app', 'warning');
+        onAutofillHotkeysResult(failed) {
-            }
+            const list = String(failed || '').trim();
+            if (!list) { toast('Hotkeys updated'); return; }
+            toast('Already used by another app: ' + list +
+                  ' — pick another combo in Settings', 'warning');
         },
 
         // ---- Device-bound prefs (DPAPI-backed) ----------------------------