Widget mode

[zealsprince]

?mode=widget turns the same deployed app into an embeddable single-channel view: no sidebar, no server browser, no settings, an Open in Orbit escape hatch, media permissions left to the iframe's allow attribute. One bundle, no version drift.

Spec

• Clients - the snippet and constraints
• Clients architecture - the constrained presentation

Acceptance criteria

• The spec's two-line iframe snippet produces a working single-channel widget
• Widget mode shows no sidebar, server browser, or settings surface
• Open in Orbit tries the desktop client and falls back to the full web app
• Voice works when the embedder grants microphone permission; without it, voice affordances explain what's missing

Blocked by #73 (message log) and #89 (connect machinery).