feat: man page (clectio.1), installed by make install

Add a manual page covering usage, the -a/-g and --month options, the compile-
time config.h settings (FORM/SIGLA/COLOR/GOSPEL_ONLY/WRAP), and both the
bring-your-own-Bible and bring-your-own-calendar workflows, matching the README.
Install it via make (MANPREFIX = $PREFIX/share/man); uninstall removes it too.
Renders clean under man --warnings.

Claude-Session: https://claude.ai/code/session_01S1CD1u3tgSS4xNu6WHfp5a

3 files changed, 162 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index c22556a..f114488 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,8 @@ CFLAGS  = -std=c99 -Os -Wall -Wextra
 # string-table pointers in at link time instead of emitting ~57 KB of runtime
 # relocations -- a ~6% smaller binary for free.
 LDFLAGS = -s -no-pie
-PREFIX  = /usr/local
+PREFIX   = /usr/local
+MANPREFIX = $(PREFIX)/share/man
 
 # The form to build is read from config.h so there is one source of truth.
 FORM   := $(shell grep -Eq '^[[:space:]]*\#[[:space:]]*define[[:space:]]+FORM_EF' config.h 2>/dev/null && echo ef || echo of)
@@ -53,9 +54,11 @@ size: clectio
 
 install: clectio
 	install -Dm755 clectio $(DESTDIR)$(PREFIX)/bin/clectio
+	install -Dm644 clectio.1 $(DESTDIR)$(MANPREFIX)/man1/clectio.1
 
 uninstall:
 	rm -f $(DESTDIR)$(PREFIX)/bin/clectio
+	rm -f $(DESTDIR)$(MANPREFIX)/man1/clectio.1
 
 clean:
 	rm -f clectio mktext bin2h text.lz.h gen/verses_of.keys gen/verses_ef.keys
diff --git a/README.md b/README.md
index 8f6c678..5429ea0 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ the Go engine that computes and generates clectio's data.
     ./clectio -a              # all readings (override a Gospel-only build)
     ./clectio --month         # this month at a glance (day, colour, celebration)
     ./clectio --month 2026-04 > apr.txt   # a month to a file for reference
-    make install              # into $PREFIX/bin (default /usr/local)
+    make install              # binary into $PREFIX/bin, man page into $PREFIX/share/man
 
 Needs only a C99 compiler and libc. It builds in about a second.
 
@@ -184,6 +184,7 @@ guessed. To extend the range, regenerate `gen/` with lectio's `clectio-gen`
     puff.c/.h        DEFLATE decompressor (Mark Adler's puff, public domain)
     mktext.c         build tool: resolve verse keys against a corpus, gzip-pack the text
     bin2h.c          build tool: embed the packed text as C
+    clectio.1        the manual page (installed by make install)
     gen/             generated, corpus-independent data (calendar + citations)
     text_of.lz       the default Vulgate text, DEFLATE-packed (one per form)
 
diff --git a/clectio.1 b/clectio.1
new file mode 100644
index 0000000..1083630
--- /dev/null
+++ b/clectio.1
@@ -0,0 +1,156 @@
+.TH CLECTIO 1 "2026" "clectio" "User Commands"
+.SH NAME
+clectio \- tiny, fast, offline Catholic daily readings
+.SH SYNOPSIS
+.B clectio
+.RB [ \-a | \-g ]
+.RI [ YYYY\-MM\-DD ]
+.br
+.B clectio \-\-month
+.RI [ YYYY\-MM " | " N ]
+.SH DESCRIPTION
+.B clectio
+prints the Catholic liturgical day and its Mass readings for a date, entirely
+offline. It computes nothing at run time: the calendar, the reading citations
+and the scripture text are all compiled into the binary, so a date is a table
+lookup. With no date it prints today.
+.PP
+One liturgical form, citation dialect and scripture text are built into a given
+binary; all of that is compile\-time configuration (see
+.BR CONFIGURATION ).
+The default text is the public\-domain Latin Vulgate. The compiled calendar
+covers 2025\-2054; a date outside that range is reported, not guessed.
+.SH OPTIONS
+.TP
+.BR \-a ", " \-\-all
+Print all of the day's readings, overriding the compiled default.
+.TP
+.BR \-g ", " \-\-gospel
+Print only the Gospel, overriding the compiled default.
+.TP
+.B \-\-month
+List a whole month, one line per day: weekday, day, liturgical colour and
+celebration (no readings). Takes an optional
+.I YYYY\-MM
+or a bare month number
+.RI ( N ,
+in the current year); with no argument, the current month. Useful piped to a
+file as a reference.
+.TP
+.BR \-h ", " \-\-help
+Print usage and the compiled configuration, and exit.
+.SH CONFIGURATION
+There is no run\-time configuration file. Options are set at compile time in
+.IR config.h ,
+copied from
+.I config.def.h
+on first build \(em edit it, then run
+.BR make .
+.TP
+.BR FORM_OF " / " FORM_EF
+Ordinary Form (post\-1969) or Extraordinary Form (1962). Enable exactly one.
+.TP
+.BR SIGLA_ENGLISH " / " SIGLA_LATIN
+Citation dialect: \(dqJer 14\(dq versus \(dqIer 14\(dq. Enable exactly one.
+.TP
+.B COLOR
+Colour the day name with its liturgical colour on a terminal (1 on, 0 off).
+.TP
+.B GOSPEL_ONLY
+Default reading set: all readings (0) or the Gospel only (1). Override per run
+with
+.BR \-a / \-g .
+.TP
+.B WRAP
+Wrap reading text at N columns;
+.B 0
+fits the terminal, and leaves piped output one line per verse.
+.PP
+One form per binary; build twice for both. The interface is English only.
+.SH BRING YOUR OWN BIBLE
+The default build embeds the Latin Vulgate. To build with another translation,
+pass a corpus \(em a six\-column TSV
+.RB ( Book ", " Abbrev ", " BookNum ", " Chapter ", " Verse ", " Text ,
+in Vulgate chapter/verse numbering) \(em to
+.BR make :
+.PP
+.RS
+.B make CORPUS=/path/to/bible.tsv
+.RE
+.PP
+clectio matches a citation on Book+Chapter+Verse and prints Text; Abbrev and
+BookNum are ignored, but the columns must be present. A verse the corpus lacks
+prints blank; it never fails the day. See the README for the full format, an
+example, and how to switch back.
+.SH BRING YOUR OWN CALENDAR
+Out of the box the calendar is the universal Roman calendar, compiled in. It can
+be changed in two tiers, because clectio has no calendar engine.
+.PP
+.B Minor \(em name and colour of a fixed date, standalone.
+Edit
+.I calendar.h
+(copied from
+.IR calendar.def.h ),
+add a
+.B { month, day, colour, "name" }
+row, and
+.BR make .
+It replaces that fixed date's name and colour every year, in both the single\-day
+and
+.B \-\-month
+output. It cannot change a day's readings or rank, place movable feasts, or
+arbitrate precedence \(em an override wins unconditionally.
+.PP
+.B Full \(em readings, ranks, movable feasts, via lectio.
+Describe the change as a
+.BR lectio (1)
+calendar layer
+.RB ( "lectio \-\-cal\-dump" ),
+then regenerate clectio's tables with it applied and recompile \(em from the
+lectio source tree:
+.PP
+.RS
+.nf
+go run ./cmd/clectio\-gen \-caldir DIR \-use NAME new 2025 2054 gen/
+make CORPUS=.../vul.tsv
+.fi
+.RE
+.PP
+The running binary stays standalone; only regenerating needs lectio and a Go
+toolchain. See the README for the full workflow and a revert note.
+.SH FILES
+.TP
+.I config.def.h
+Template for the compile\-time configuration; copied to
+.I config.h
+on first build.
+.TP
+.I calendar.def.h
+Template for local calendar overrides; copied to
+.IR calendar.h .
+.TP
+.I gen/
+Generated, corpus\-independent tables (calendar, citations, verse keys).
+.TP
+.IR text_of.lz ", " text_ef.lz
+The packed scripture text for each form (default: the Latin Vulgate).
+.SH EXIT STATUS
+.TP
+.B 0
+Success.
+.TP
+.B 1
+The date is outside the compiled range.
+.TP
+.B 2
+Usage error (bad option, date or month).
+.SH SEE ALSO
+.BR lectio (1)
+.PP
+The full manual \(em corpus format, calendar customization, sizing \(em is the
+project README.
+.SH LICENSE
+ISC (clectio's own code). The compiled scripture text is a separate work under
+its own terms; the default Latin Vulgate is public domain.
+.SH AUTHOR
+Łukasz Kasprzak.