feat(cli): --version, a CHANGELOG, and a release target

Groundwork for tagging. The project had no version anywhere: not in
dune-project, not in the binary, no CHANGELOG, no tags.

The version lives in two places -- dune-project, which generates
colitur.opam, and a constant in bin/main.ml, which is what --version
prints. Two rather than one because dune's watermarking only substitutes
in a release tarball, so a binary built the ordinary way from a checkout
would report a placeholder. The release target rewrites both and then
re-checks both, and finally requires the freshly built binary to report
the version it just wrote: a release that bumped one and not the other
would ship a binary disagreeing with its own package metadata.

--version is deliberately not embedded in the help text. cli.t pins
help's first line, and a version there would mean editing a test
expectation every release for no gain.

The release target mirrors lectio's, refusals included: no release from a
dirty tree, none without a CHANGELOG entry for that version, none whose
version bump silently failed to apply, and `make check` -- the full
1583-9999 sweep, not the sampling suite -- must pass before the tag is
created.

1 files changed, 6 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
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+# Changelog
+
+One line per release. Versions are git tags (`vX.Y.Z`).
+
+## [0.1.0] - 2026-08-17
+- First tag. The Extraordinary Form (1962 Roman Missal) end to end: the complete temporal cycle, the resolution engine (occurrence, precedence, commemorations, transfers) against the sanctoral calendar, and the Mass reading citations for every day — correct and total over 1583–9999, with no clock, randomness or environment read below the CLI. Four commands (`easter`, `temporal`, `day`, `readings`) plus `--help`/`--version`, a man page, and a Makefile that installs binary, calendar data and man page into `~/.local` by default. Validated in five layers: types, QCheck properties over every year in the domain, a 16 801-day differential against the sibling lectio engine, two independent missalemeum oracle windows (2026–2027 and 2038), and ~36 hand-verified golden pins — 375 tests. Rules are computed against the Missal and its *Rubricae Generales*, with every published-calendar divergence adjudicated against the primary text rather than adopted; several are resolved in this engine's favour and cited in the register. Not included: the Ordinary Form, the chants (Psalm/Gradual/Tract/Alleluia/Sequence, deliberately rejected rather than guessed), and template-driven output.