Reparents Teams' main top-level window into a TeamsISO-owned host via Win32 SetParent + window-style stripping. Operator gets Teams visually INSIDE TeamsISO instead of as a separate window — completes the 'Teams runs within this app' direction the user asked for after auto-hide.
Strictly opt-in (DISPLAY tab → 'Embed Teams window (experimental)'). Modern Teams runs WebView2 in its main window; WebView2 is sensitive to parent changes and may render glitches or refuse focus. If so, operator unticks and falls back to auto-hide mode.
Implementation:
- TeamsLauncher.EmbedTeamsInto(hostHwnd, w, h): finds Teams' main window (longest-title heuristic — same as GetActiveWindowTitle), saves original parent + WS_STYLE, SetParents into host, strips WS_CAPTION + WS_THICKFRAME + WS_BORDER + WS_DLGFRAME + WS_POPUP, adds WS_CHILD, MoveWindow to fit.
- TeamsLauncher.RestoreEmbed(): SetParent back to desktop + restore saved window styles. Idempotent — safe to call on shutdown even if nothing was embedded.
- TeamsLauncher.ResizeEmbedded(w, h): MoveWindow to new dimensions; called from host SizeChanged event.
- New TeamsEmbedWindow chromeless host with an EXPERIMENTAL pill in the caption. Loaded → grab HwndSource from EmbedHost Border → call EmbedTeamsInto. SizeChanged → ResizeEmbedded. Closed → RestoreEmbed (in try/finally so a crash can't leave Teams orphaned). Friendly fallback messages if no Teams window exists or HWND grab fails.
- Settings → DISPLAY → checkbox + 'Open embed window' button (gated by the checkbox). Persisted via EmbedTeamsWindow on UIPreferences.
