- Swap the command deck's "Build" slot for a "Scan" slot that fires an
omnidirectional sonar pulse from the ship across the tether region.
- The wavefront is clipped to the union of tether circles: it is absorbed
at the rim (bright absorbing arc + TetherField.excite shiver) instead of
flying into empty space.
- Objects inside the region ring as the front crosses them (shock rings,
RGB ghost, scale pulse); the starfield ripples and the camera thumps /
rolls with the wave, then restores itself on completion or cancel.
- New modules: js/scan/ScanPulse.js (rendering + lifecycle),
js/scan/ScanGeometry.js (pure circle-circle window math).
- All tuning lives in data/scan.json; the one SFX is the new "scan" key
in data/sfx.json. Results are a seam for now — finishScan logs the
in-region objects and reports the count in the console slot.
- Tests: dev/scan.test.mjs (geometry unit tests) and
dev/scan-test.html/.mjs (headless flow test driving the real scene).
- Add Terran shop placeholder assets (two PNGs + one MP4).
