erga 0.27.0 — a battery for the wait

Download erga-0.27.0-arm64.dmg, drag to Applications, then:

xattr -dr com.apple.quarantine /Applications/erga.app

Added

• A battery for the table build. Pressing the crystal is followed by a wait
  while the epoch table is built, and until now that wait was a black box.
  Beside building table… there is now a battery filling up and a percentage,
  and both breathe — a pulse soft enough not to nag and quick enough to say
  working, not stuck. Measured at 1.48× between trough and peak on a 1.8 s
  cycle.

  The progress is real, not a stopwatch pretending. The build kernel takes a
  row offset, so the build is dispatched in eight pieces and each one reports
  as it lands — through the miner's STAT line into the window. erg mine
  prints it too.

Measured

Piece count swept on an idle M4 Max (227M rows, 6.77 GiB):

pieces	build
1	13.20 s
4	11.67 s
8	13.37 s
16	14.89 s (+13%)
64	21.49 s (+63%)

Run-to-run spread is about 1.5 s, so the eight pieces the meter needs are free.
ERGA_BUILD_PIECES sweeps it. An earlier sweep run while two other builds were
pinning the CPU reported a 23% cost that does not exist — measure this idle.

Zero clippy findings across the workspace; 19 tests.