Typemap / exclusive-lock (+l) manager for Unreal binaries

- Tools -> Exclusive Locks (typemap): view/edit server typemap, one-click add
  recommended binary+l rules for UE asset types (.uasset/.umap/.fbx/textures/etc)
- Per-file 'Set exclusive-lock type (+l)' in the Changes context menu
- Backend p4 typemap -o/-i and reopen -t

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

src/App.css

@@ -794,6 +794,7 @@ body.resizing-v{cursor:row-resize!important;user-select:none}
 .rslv-act svg{width:14px;height:14px;display:block}
 .lk-who{flex:0 0 auto;display:flex;flex-direction:column;align-items:flex-end;gap:1px;font-size:11.5px;color:var(--muted);max-width:170px}
 .lk-client{font-size:10px;color:var(--faint);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:170px}
+.tm-hint{padding:10px 16px;font-size:11.5px;line-height:1.5;color:var(--faint);border-bottom:1px solid var(--border-soft)}
 /* blame + diff panes */
 .picker.blame{width:900px;height:640px}
 .blame-body,.diff-body{flex:1;overflow:auto;padding:8px 0;font-family:var(--mono);font-size:12px;line-height:1.5;background:var(--stage-bg)}