tooltip: clamp box width to client on narrow panels; add narrow-client test

src/bank_panel.cpp

@@ -1098,6 +1098,9 @@ bool currentTooltip(int w, int h, std::string& textOut, int& ax, int& ay, int& a
 
     // The full name is stored already prefix-free, but strip defensively in case a source ever
     // carries the "ReaSampler:" display prefix (the tooltip must never show it — L5 refinement 2).
+    // Intentionally distinct sources: the tooltip reads the registered phrase (fullName) while the
+    // keybinding sub-row in drawToolbar reads the live binding via kbd_getTextFromCmd. Do not
+    // unify them — each serves a different purpose and has a different lifetime.
     textOut = stripActionPrefix(rows[static_cast<std::size_t>(hv.index)].fullName,
                                 actionDisplayPrefix());
     ax = slot->x; ay = slot->y; aw = slot->width; ah = slot->height;