feat(call): screenshare from inside the frame where delegation is missing; host stops reading the call frame (#43)

Firefox, Safari and the WebKitGTK desktop app can't hand the user's click to
the call frame (no Capability Delegation), and getDisplayMedia needs it. The
host used to click EC's hidden footer button through the DOM instead, which
dies with same-origin. Now (pins element-call-embedded 0.25.0-lotus.20):

- those engines get `lotusFrameScreenshare`, the fork shows EC's own
  screenshare button in the frame, and the call bar and status bar hide
  theirs once controls_state reports `frameScreenshare`; the
  screenshare-audio mute stays;
- the room's call policy is pushed with io.lotus.set_frame_screenshare, so
  the frame button hides where the server would refuse a share, like ours;
- Chromium keeps the delegated io.lotus.set_screenshare from the host bar.

Removed the fallbacks for forks older than lotus.14, which read or clicked
EC's DOM: the screenshare/layout/settings/reactions/leave button lookups
and their MutationObservers, the frame-window hotkey binding, and the
speaking/muted tile scrape in useCallSpeakers (io.lotus.call_state is the
only source now). getCallDocument is gone; the host's only handle on the
frame is postMessage.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/hooks/useCallHotkeys.ts

@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from 'react';
+import { useEffect, useRef } from 'react';
 import { atom, useSetAtom } from 'jotai';
 import { CallEmbed, useCallControlState } from '../plugins/call';
 import { useSetting } from '../state/hooks/settings';
@@ -105,32 +105,6 @@ const isInteractive = (el: HTMLElement): boolean => {
   return false;
 };
 
-/**
- * Bind listeners to the EC iframe's window and keep them bound across document
- * reloads. [Gitea #60] Listeners registered on a contentWindow are discarded
- * when that window navigates to a new document (crash recovery, in-widget
- * navigation), so re-run `bind` from the iframe's `load` event and detach the
- * previous set. Returns a cleanup that detaches everything.
- */
-const bindIframeWindow = (
-  iframe: HTMLIFrameElement,
-  bind: (win: Window) => () => void,
-): (() => void) => {
-  let unbind: (() => void) | undefined;
-  const attach = () => {
-    unbind?.();
-    const win = iframe.contentWindow;
-    unbind = win ? bind(win) : undefined;
-  };
-  attach();
-  iframe.addEventListener('load', attach);
-  return () => {
-    iframe.removeEventListener('load', attach);
-    unbind?.();
-    unbind = undefined;
-  };
-};
-
 /**
  * Push-to-talk and deafen hotkeys for the active call.
  *
@@ -150,20 +124,6 @@ export function useCallHotkeys(callEmbed: CallEmbed | undefined, joined: boolean
   const { microphone } = useCallControlState(embed?.control);
   const setPttActive = useSetAtom(pttActiveAtom);
 
-  // [Gitea #43] Once the fork reports it handles hotkeys, keys pressed inside
-  // the call frame arrive as io.lotus.hotkey and we stop adding listeners to
-  // the frame's window (which needs same-origin access).
-  const [forkHotkeys, setForkHotkeys] = useState(false);
-  useEffect(() => {
-    if (!embed) {
-      setForkHotkeys(false);
-      return undefined;
-    }
-    const sync = () => setForkHotkeys(embed.control.forkHandlesHotkeys);
-    sync();
-    return embed.control.onForkHotkeysChange(sync);
-  }, [embed]);
-
   // Track microphone via ref so the PTT effect doesn't need it as a dep (avoids listener churn)
   const microphoneRef = useRef(microphone);
   useEffect(() => {
@@ -268,25 +228,23 @@ export function useCallHotkeys(callEmbed: CallEmbed | undefined, joined: boolean
       };
     };
     const unbindHost = bind(window);
-    // BUG-9: PTT also works with focus in the call frame — reported by the
-    // fork, or (older fork) via listeners on the frame's window.
+    // BUG-9: PTT also works with focus in the call frame, reported by the
+    // fork (io.lotus.hotkey; the host no longer listens on the frame's window).
     embed.control.setHotkeyCodes('ptt', [pttKey]);
     const unbindFork = embed.control.onHotkey((r) => {
       if (r.type === 'focus') onFocusChange();
       else if (r.type === 'keydown') pttDown(r, r.editable, r.interactive);
       else if (r.code === pttKey) release();
     });
-    const unbindIframe = forkHotkeys ? () => undefined : bindIframeWindow(embed.iframe, bind);
     return () => {
       unbindHost();
       unbindFork();
-      unbindIframe();
       embed.control.setHotkeyCodes('ptt', []);
       // BUG-8: if the embed changes while PTT is active, release mic on cleanup
       if (pttActiveRef.current) release();
     };
     // microphone intentionally read via microphoneRef — excluded from deps to avoid listener churn
-  }, [pttMode, pttKey, embed, setPttActive, forkHotkeys]);
+  }, [pttMode, pttKey, embed, setPttActive]);
 
   // [cinny-desktop #2] System-wide PTT/deafen while a game has focus. The
   // desktop polls the configured keys without consuming them and emits one
@@ -366,17 +324,10 @@ export function useCallHotkeys(callEmbed: CallEmbed | undefined, joined: boolean
         embed.control.toggleSound();
       }
     });
-    const unbindIframe = forkHotkeys
-      ? () => undefined
-      : bindIframeWindow(embed.iframe, (win) => {
-          win.addEventListener('keydown', onKeyDown);
-          return () => win.removeEventListener('keydown', onKeyDown);
-        });
     return () => {
       window.removeEventListener('keydown', onKeyDown);
       unbindFork();
-      unbindIframe();
       embed.control.setHotkeyCodes('deafen', []);
     };
-  }, [embed, deafenKey, deafenHotkey, forkHotkeys]);
+  }, [embed, deafenKey, deafenHotkey]);
 }