feat(call): stop injecting CSS and key listeners into the call frame (#43)

Pins @lotusguild/element-call-embedded 0.25.0-lotus.19.

- Styles: the fork now hides its own footer (`lotusHostControls=1`) and
  sets its root color-scheme from the theme, so the host no longer
  injects `#lotus-ec-styles` or sets inline styles on EC's DOM. The two
  other injected rules matched nothing in EC 0.25 (dead). The
  transparent background was already the fork's (`lotusTransparent`).
- Hotkeys: PTT / deafen keys pressed with focus inside the call frame now
  arrive as `io.lotus.hotkey` (the host sends the codes via
  `io.lotus.set_hotkeys`), instead of listeners on the frame's window.
  The window binding stays only for a fork that doesn't report `hotkeys`.
- Fixes (with lotus.19): pressing the deafen key M with focus in the call
  also hit EC's own "M = toggle mic" shortcut, so the first press turned
  the mic ON instead of deafening — even in push-to-talk mode.

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

package-lock.json

@@ -81,7 +81,7 @@
       },
       "devDependencies": {
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-        "@lotusguild/element-call-embedded": "0.25.0-lotus.17",
+        "@lotusguild/element-call-embedded": "0.25.0-lotus.19",
         "@playwright/test": "1.63.0",
         "@rollup/plugin-inject": "5.0.5",
         "@rollup/plugin-wasm": "6.2.2",
@@ -2695,9 +2695,9 @@
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     },
     "node_modules/@lotusguild/element-call-embedded": {
-      "version": "0.25.0-lotus.17",
-      "resolved": "https://code.lotusguild.org/api/packages/LotusGuild/npm/%40lotusguild%2Felement-call-embedded/-/0.25.0-lotus.17/element-call-embedded-0.25.0-lotus.17.tgz",
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+      "version": "0.25.0-lotus.19",
+      "resolved": "https://code.lotusguild.org/api/packages/LotusGuild/npm/%40lotusguild%2Felement-call-embedded/-/0.25.0-lotus.19/element-call-embedded-0.25.0-lotus.19.tgz",
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       "dev": true
     },
     "node_modules/@matrix-org/matrix-sdk-crypto-wasm": {