Add printer.conf for DFX-5000+ on single A4 sheets

Separate from printer.conf.epsondfx5kp.bak's fanfold arrangement: this
install runs the DFX-5000+ on cut A4 sheets (measured 70 lines x 80
columns) rather than wide continuous fanfold, and A4 mode is now known
to work and use the sheet fully, so PRINTER_A4=true here instead of
wasting paper in portrait. Also notes that the fanfold config's
11-inch DIP page-length setting doesn't match true A4 sheet length and
was causing a repeatable skip - the datasheet's 70-line/6lpi option is
the fix for this arrangement.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

printer.conf.epsondfx5kpA4.bak

@@ -0,0 +1,47 @@
+# ASCII Photobooth printer configuration
+# Sourced by txt2printr.sh and photobooth.py.
+
+# Is the printer loaded with A4 paper for a landscape printout? (true/false)
+# Needle/dot-matrix printers have no hardware page-rotation command: the
+# print head only scans across a fixed carriage width while the paper feeds
+# in one fixed direction, so there is no way to make the physical page
+# itself "landscape". Instead, when this is true:
+#  - txt2printr.sh rotates the ascii art 90 degrees in software before
+#    sending it to the printer (turn the printed page 90 degrees to read it)
+#  - photobooth.py sizes its live-preview viewfinder to an A4-landscape
+#    character grid instead of just following the terminal size, so what you
+#    see in the preview matches the shape of what gets printed
+# This install is loaded with single-sheet A4 stock (not the wide 4-16in
+# fanfold covered by printer.conf.epsondfx5kp.bak) and actually prints on
+# it fine, so this stays true - running the unrotated portrait variant on
+# this narrower stock wastes paper instead of using the full sheet.
+PRINTER_A4=true
+
+# Your printer's real per-page capacity in the normal (portrait, unrotated)
+# orientation, used to size the A4 viewfinder above and to know when a print
+# job already fills the page (see txt2printr.sh). Paper geometry and stated
+# pitch don't reliably predict this - measure it directly with pagetest.sh:
+#   ./pagetest.sh && PRINTER_A4=false ./txt2printr.sh pagetest.txt
+# then read off the last line number on page 1 (-> PRINTER_MAX_LINES) and
+# how many characters of the 64-wide test lines actually printed before
+# being cut off (-> PRINTER_MAX_COLS).
+#
+# Measured on this A4 sheet arrangement: 70 lines, 80 columns.
+#
+# Unlike printer.conf.epsondfx5kp.bak (PRINTER_MAX_LINES=0, treated as
+# unbounded roll stock), this arrangement uses real single A4 sheets, so a
+# fixed page length applies here and PRINTER_MAX_LINES is non-zero. This
+# matters beyond just the end-of-job form feed in txt2printr.sh: this A4
+# sheet's true page length (297mm / 11.69in) does not match the DFX-5000+'s
+# "11-inch" DIP page-length option documented in epson5kp-dipsettings.md for
+# the fanfold arrangement (SW3-1/3-2 OFF, OFF). Running that mismatched
+# setting on A4 stock was the cause of a repeatable skip (blank gap starting
+# 8 lines into the printed image, 6 lines tall - a 1in perforation-skip gap
+# at 6 lpi firing at the wrong spot because the printer's idea of the page
+# boundary drifted from the real one). The datasheet's "70 lines/6 lpi"
+# page-length option (70 lines * 1/6 in = 11.67in) matches this A4 sheet
+# length far more closely than the 11-inch option and is what SW3-1/3-2
+# should be set to for this arrangement instead - see epson5kp-dipsettings.md
+# for the fanfold DIP baseline this varies from.
+PRINTER_MAX_LINES=70
+PRINTER_MAX_COLS=80