fix(calls): hotkey rebind denylist; ignore modifiers; keep Space on buttons

- useKeyBind refuses Tab/Enter/arrows/Home/End/Page*/Escape and bare
  modifier codes, and refuses a code equal to the other call key, with an
  inline message (isBindableCallKey, unit-tested).
- PTT and deafen handlers ignore events with Ctrl/Alt/Meta held (deafen
  also Shift), so Cmd+M / Ctrl+M no longer toggle deafen.
- PTT only preventDefault()s when the target is not an interactive
  control, so Space still activates focused buttons during a call.

Fixes #23

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/call/CallControls.tsx

@@ -171,6 +171,10 @@ export function CallControls({ callEmbed }: CallControlsProps) {
 
     const onKeyDown = (e: KeyboardEvent) => {
       if (e.code !== pttKey || e.repeat) return;
+      // [Gitea #23] Ignore the PTT key with Ctrl/Alt/Meta held so it doesn't
+      // hijack OS/app chords (e.g. Cmd+Space) that happen to share the code.
+      // Shift is allowed through — Shift+Space is a harmless combo for PTT.
+      if (e.ctrlKey || e.altKey || e.metaKey) return;
       const target = e.target as HTMLElement;
       // BUG-7: use ownerDocument.body so isEditable works inside the EC iframe
       const isEditable = (el: HTMLElement): boolean => {
@@ -185,7 +189,23 @@ export function CallControls({ callEmbed }: CallControlsProps) {
         return false;
       };
       if (isEditable(target)) return;
-      e.preventDefault();
+      // [Gitea #23] Don't swallow Space on a focused button/link/etc — PTT still
+      // engages the mic, but the key's default action (activating the control)
+      // is left alone so keyboard users can still Tab+Space the call buttons.
+      const isInteractive = (el: HTMLElement): boolean => {
+        const tag = el.tagName;
+        if (tag === 'BUTTON' || tag === 'A' || tag === 'SELECT') return true;
+        let node: HTMLElement | null = el;
+        while (node && node !== el.ownerDocument.body) {
+          const role = node.getAttribute('role');
+          if (role === 'button' || role === 'link' || role === 'menuitem' || role === 'tab') {
+            return true;
+          }
+          node = node.parentElement;
+        }
+        return false;
+      };
+      if (!isInteractive(target)) e.preventDefault();
       // C-M5: mark PTT active BEFORE unmuting so the mic echo (onMediaState)
       // doesn't treat this transient unmute as a user-initiated undeafen.
       callEmbed.control.pttActive = true;
@@ -256,6 +276,10 @@ export function CallControls({ callEmbed }: CallControlsProps) {
     const onKeyDown = (e: KeyboardEvent) => {
       if (e.code !== deafenKey) return;
       if (e.repeat) return;
+      // [Gitea #23] Ignore the deafen key with any modifier held — with the
+      // default 'KeyM', Ctrl+M / Alt+M / Cmd+M are common OS/app chords that
+      // shouldn't also toggle deafen (and previously got preventDefault()ed).
+      if (e.ctrlKey || e.altKey || e.metaKey || e.shiftKey) return;
       if (isEditable(e.target as HTMLElement)) return;
       e.preventDefault();
       callEmbed.control.toggleSound();