v0.6.0 — the night on the ledger

v0.4.0 taught the forecast that you sleep. The ledger still did not know:

▂▃▅▁▂▄█▃▁▁▂▅▄▃▁▂▃▅▄▂▁▃▄▅▃▂▮▯▯▯▯▯▯▯

Nine hollow cells, all drawn the same, and three of them are the middle of
two nights. The row said "nine slots ahead" while the budget line beside it
said ~6 awake — one surface counting clock, the other already counting
yours.

The future is a shape, not a count

An ahead-cell whose 5h slot has under REST_SLOT_AWAKE_MIN_SECS (9000 —
half a window) of waking seconds now draws DIM. Same ▯: the glyph is the
fact, the tint is the refinement, and a reader who cannot see the tint
loses nothing they could have acted on — a dim ▯ is still a window ahead,
it is just one the capacity is unlikely to reach. Waking hours are the
v0.4.0 arithmetic exactly (mult >= REST_MULT_MAX over the slot's real
wall span), so nothing here is a second opinion about your day.

The wall span is the whole rule. 20:00–01:00 and 05:00–10:00 straddle the
same night's two edges and the hour a slot OPENS in gets both of them
wrong: the first is four waking hours and a window you can spend, the
second is two and a night. On the 5h grid every slot straddles something.

Gated on the evidence the walk already needs — a valid hour_profile and
FORECAST_MIN_DAYS of history. Unlearned, the row is byte-for-byte the
row it was in v0.5.0, tints and all, and the tests hold it there against
every way of not knowing: no field, a truncated one, a nonsense one, a
real one with a fortnight of history missing behind it.

× beats rest — a slot the pool will not cover is unreachable for a
stronger reason than sleep, and drawing it as a night would hide that. ▮
and every cell of the record are untouched.

Same rule on both surfaces

REST_SLOT_AWAKE_MIN_SECS is a shared READING RULE, not a cache field:
statusline v0.38.0 dims the same slots on its own 7d strip (and each rest
hour on the 5h one) off the same forecast.cache. schema stays 2; no
field moved. Documented in docs/statusline-interop.md. The dim cells and
the budget's ~N awake may differ by one — the strip is a grid on the
period start, the count comes from real clocks — the same tolerance the
window count itself already carries.

Internally the two now share one awake_seconds(); the budget's count and
the ledger's nights were never allowed to be two implementations.