Implement embedded build for cockpit with host app integration

.gitignore

@@ -7,3 +7,6 @@ build/icon.png
 
 # tooling scratch
 .playwright-mcp/
+
+# Embedded build consumed by a host app (npm run build:renderer:embed)
+dist-embed/

LICENSE

@@ -0,0 +1,26 @@
+MIT License
+
+Copyright (c) 2026 Daniel Trujillo
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+Portions of this software are derived from third-party projects and remain
+under their own licenses. Each derived file carries the upstream notice, the
+license identifier and a statement of changes in its header. The principal
+upstream sources are listed under Credits in README.md.

docs/media/README.md

@@ -0,0 +1,51 @@
+# Media assets
+
+Images referenced by [README.md](../../README.md). Every file here is generated
+from this repository's own code, not captured by hand.
+
+| File | Size | Source |
+|---|---|---|
+| `banner.webp` | 1280x400 | The `willidream` still under a scrim, with the wordmark in the bundled Source Code Pro |
+| `hero.webp` | 1280x720 | The `miraclemile` still, DETONATION act |
+| `scenes/<id>.webp` | 480x270 | One still per registry scene, `<id>` matching `meta.id` in `src/renderer/engine/scenes/` |
+
+## Regenerating the scene stills
+
+`gallery.plan.json` is the scene-harness plan the stills come from. It carries
+one entry per scene in registry order, each with the exact `io` snapshot
+(palette, bands, level, beat, knobs, gestures, strikes, transport) that the
+scene was photographed under.
+
+```sh
+node scripts/scene-harness.js docs/media/gallery.plan.json
+```
+
+The harness renders in a hidden Electron window and writes one PNG per shot to
+`%TEMP%/swaycommand-harness` unless the plan sets `out`. Shots whose name starts
+with an underscore exist to advance a scene into the state the next shot
+photographs: `_willidream_bang` runs the universe from the singularity through
+the big bang so that `willidream` can fire a hyperspace jump into a settled star
+field, and `_miraclemile_open` moves the act knob off zero so that the act
+change registers as a move rather than an initial value.
+
+Two properties of the harness affect what comes back. Scene instances are cached
+across shots, so a scene's shots must stay contiguous and in order. The clock
+`t` is shared by every shot in a run, so a scene's absolute time depends on what
+ran before it; re-running the plan reproduces the setup exactly and the frame
+approximately.
+
+The PNGs are then scaled and re-encoded to WebP at quality 0.80 (0.86 for the
+hero) through a canvas in the same Electron runtime. There is no native image
+dependency in this tree.
+
+Cold-cache warning: on a GPU shader cache that has never seen these scenes,
+`miraclemile` and `naturestomb` block the calling thread for one to two minutes
+on their first draw. That is the open compile regression recorded in
+[HANDOFF.md](../../HANDOFF.md), not a harness fault. A second run is fast.
+
+## Replacing a still with a recording
+
+The README references each scene by path, so a recording replaces a still by
+taking its name. An animated `scenes/<id>.gif` supersedes `scenes/<id>.webp`
+once the link in README.md points at it. Keep the 16:9 frame and a width of 480
+so the gallery grid stays even.