Fire that looks like fire, a rack you can leave, and a boss you can read

The band work from f352612 rides along; everything else is this round's list.

- proj returns a NEGATIVE scale behind the camera, so four ellipse call sites
  could be handed negative radii — ctx.ellipse throws on those, and the throw
  killed the rest of the frame (no HUD, no rack, no band). All four now skip
  points behind the camera.
- a burst tin is no longer a commitment: tapping another slot aborts it, spends
  it and hands back the serve loop. Lives in selectWeapon, so the rack tap and
  the 1-0 keys both get it. A horde still locks the rack — that is the one place
  your finger is already spoken for. Spending splices the rack, so the tap
  resolves to a weapon id and re-finds it rather than trusting the index.
- beacon 1.6 -> 2.4 rounds/s: a lob cannon you could not leave AND could not
  feel working was two problems.
- FIRE. Flamer throws fat embers instead of a one-pixel thread; burning bodies
  get nine tongues over a heat bloom plus smoke; the fire ball gets a halo and a
  real tail; an ash death gets twice the motes at twice the life over a ground
  bloom and a column. The flamer had no sfx case at all and was using the gun's
  dry tick — it has its own roar now.
- chapter bosses carry an HP bar over their head. The no-HP-bar rule stands for
  everything else and the comment says why a boss is the exception.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

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