Document Twitch video overlay milestone

.labyricorn/devlog/twitch-video-overlay/contents.lr

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+_model: devlog-entry
+---
+schema_version: 1
+---
+title: Twungeon controls move into the Twitch video overlay
+---
+date: 2026-08-17
+---
+author: Codex and Christopher Chambers
+---
+summary: Twungeon replaced its component-style viewer popup with a transparent, responsive Twitch video overlay that reuses the authenticated controller while leaving the streamed dungeon visible.
+---
+tags: implementation, deployment, Twitch, Twitch Extension, video overlay, responsive UI, accessibility, testing
+---
+source_commit: a8a86852c0e06e518d816ea35400ef9878a365f3
+---
+body:
+
+Twungeon's viewer controls now sit directly over the control area reserved in
+the stream instead of opening as a large Twitch Video Component popup. The
+production viewer uses Twitch's Video - Fullscreen placement with `extension`
+as its relative viewer path. The broadcast continues to provide the dungeon,
+players, Goblin, exit, status frame, and action log underneath the Extension.
+
+The change deliberately reuses the existing controller and authoritative
+backend flow. Twitch identity sharing, short-lived Twungeon sessions, character
+ownership, movement, attack, self-heal, pass, action points, phase checks, and
+dead-character checks still use the same APIs and server-side rules. The root
+page remains the complete local and broadcast view, while `/extension` receives
+an overlay class before first paint and hides every noninteractive game surface.
+
+Overlay placement is expressed through centralized percentage-based CSS
+variables for the control region rather than resolution-specific coordinates.
+Container-relative sizing keeps the directional pad and action buttons usable
+across normal, theater, fullscreen, narrow, and 4:3 players. The transparent
+document and empty overlay canvas reject pointer events; only the actual buttons
+restore them, so the rest of the video is not presented as a large clickable
+surface.
+
+Development remains practical without Twitch. The loopback-only
+`/extension?dev=1&debug=1` mode exposes the existing synthetic viewer login and
+draws control-region boundaries. The flags are ignored on the deployed host.
+Operator documentation now identifies the Twitch dashboard setting as
+**Video - Fullscreen**, records the `extension` viewer path, and separates the
+manual dashboard change from repository deployment.
+
+Live testing exposed a subtle transparency failure after the correct viewer
+path was saved. Although the document, body, and control region all computed to
+transparent backgrounds, the root `color-scheme: dark` declaration caused
+Chrome to paint the iframe canvas black. Dark color scheme now applies only to
+the full game page; overlay mode explicitly uses the normal transparent canvas.
+The stylesheet fix was deployed without restarting the Twungeon service, so the
+active in-memory run was preserved.
+
+Validation covered linting, strict type checking, 24 domain tests, 10
+integration and multi-viewer tests, and a production build. Browser checks at
+1920×1080, 1280×720, and 1024×768 confirmed normalized placement, hidden
+noninteractive surfaces, button-only pointer handling, and transparent computed
+backgrounds. The deployed public stylesheet and viewer endpoint were verified
+after the final transparency correction.
+
+The Twitch video-overlay implementation is recorded in
+[commit `a8a86852c0e06e518d816ea35400ef9878a365f3`](https://git.labyricorn.com/Labyricorn/Twungeon/commit/a8a86852c0e06e518d816ea35400ef9878a365f3).