photophone

feat(ecc): partial last RS block — use every byte of frame capacity (#37)

docs: mark M0-M14 landed, split M3.5 detail to its own file (#36)

design: window-search fiducial detection (middle tier between PR-A and full detect) (#33)

perf: incremental warped decode (rotation + fiducial cache) — 150× on the fast path (#32)

feat(m15): perf baseline + palette LUT optimization (#31)