The hour byte of a TIMED program is overloaded as a 1-of-3 discriminator:
0..23 means absolute wall-clock time, 25 means sunrise-relative, 26 means
sunset-relative. For the relative forms, the minute byte is signed
(sbyte) -- positive = after, negative = before, zero = at. Source:
frmPopUpEditTime.cs:186-217 (decode) + :241-263 (encode).
This was the canary that tripped our earlier sanity test: slots 182/183
in the live fixture have hour=26 minute=246 and hour=25 minute=10 --
nominally invalid as clock times, but they're "10 min before sunset"
and "10 min after sunrise" respectively. With this commit those decode
cleanly via TimeKind.SUNSET / SUNRISE.
omni_pca.programs:
* New TimeKind IntEnum: ABSOLUTE / SUNRISE / SUNSET.
* New Program.time_kind property (classifies via hour-byte discriminator).
* New Program.time_offset_minutes property (signed minutes-offset for
sunrise/sunset; 0 for absolute).
* New Program.format_time() -> str: "07:15" | "at sunrise" | "30 min
before sunset" etc.
* Module-level _classify_time helper + sentinel constants
_HR_SUNRISE_SENTINEL=25 / _HR_SUNSET_SENTINEL=26.
omni_pca top-level: re-exports TimeKind.
tests/test_programs.py (+13 cases):
* Parametrised TimeKind classification across absolute / sunrise /
sunset including boundary cases (sbyte ±128, ±1, 0).
* Wire-bytes round-trip preserves TimeKind + offset.
tests/test_pca_file.py: tightened the previously-loosened sanity
invariant. ABSOLUTE-time TIMED programs must hit valid wall-clock
ranges (0-23 / 0-59); relative-time programs must have a valid sbyte
offset (-128..127). Both pass cleanly on the 209 TIMED programs in
the live fixture (207 absolute, 1 sunrise, 1 sunset).
Full suite: 439 passed, 1 skipped (was 426 / 1).