chore(justfile): add sixel test recipes

After rebasing onto master (which now carries the justfile from #8),
add recipes for the new configurable encoder + timeout work:

- `sixel-encoder' prints what `kitty-gfx--sixel-resolve-encoder' picks.
- `sixel-encode [ENCODER]' encodes tests/test-image.png headlessly and
  reports payload size; pass an encoder name to force a specific binary
  (e.g. `just sixel-encode img2sixel').
- `sixel-timeout-test' verifies the watchdog kills a `sleep 60' fake
  encoder within `kitty-gfx-sixel-encoder-timeout' seconds.
- `test-sixel-image [ENCODER]' opens tests/test-image.png in Emacs with
  the Sixel backend forced, for manual rendering checks in foot/Konsole/
  mintty/mlterm/WezTerm.

1 files changed, 49 insertions, 0 deletions

diff --git a/justfile b/justfile
index 1202ca5..22fe756 100644
--- a/justfile
+++ b/justfile
@@ -98,6 +98,55 @@ typst-show fragment="$integral_(-oo)^(+oo) e^(-x^2) dif x = sqrt(pi)$":
         echo "png=$png"; \
         [ -n "$png" ] && xdg-open "$png"
 
+# --- Headless sixel checks --------------------------------------------------
+
+# Show resolved sixel encoder (auto-detect: img2sixel > magick > convert)
+sixel-encoder:
+    {{EMACS}} -Q -batch -L . -l {{SRC}} --eval '(princ (format "%S\n" (kitty-gfx--sixel-resolve-encoder)))'
+
+# Encode tests/test-image.png to sixel headlessly, report payload size.
+# Override encoder with: just sixel-encode "img2sixel"
+sixel-encode encoder="":
+    {{EMACS}} -Q -batch -L . -l {{SRC}} --eval '(progn \
+        (setq kitty-gfx-debug t) \
+        (when (> (length "{{encoder}}") 0) \
+          (setq kitty-gfx-sixel-encoder-program "{{encoder}}")) \
+        (princ (format "encoder=%S\n" (kitty-gfx--sixel-resolve-encoder))) \
+        (let ((d (kitty-gfx--sixel-encode "tests/test-image.png" 20 10))) \
+          (princ (format "bytes=%s\n" (and d (length d))))))'
+    @echo "--- log tail ---"
+    @tail -3 /tmp/kitty-gfx.log 2>/dev/null || true
+
+# Verify timeout watchdog kills a hung encoder within `kitty-gfx-sixel-encoder-timeout'
+sixel-timeout-test:
+    @printf '#!/usr/bin/env bash\nsleep 60\n' > /tmp/kgfx-fake-encoder.sh
+    @chmod +x /tmp/kgfx-fake-encoder.sh
+    time {{EMACS}} -Q -batch -L . -l {{SRC}} --eval '(progn \
+        (setq kitty-gfx-debug t \
+              kitty-gfx-sixel-encoder-program "/tmp/kgfx-fake-encoder.sh" \
+              kitty-gfx-sixel-encoder-timeout 1.0) \
+        (with-temp-buffer \
+          (set-buffer-multibyte nil) \
+          (princ (format "ok=%S\n" (kitty-gfx--sixel-run-encoder \
+                                    "/tmp/kgfx-fake-encoder.sh" 1.0 \
+                                    (current-buffer) nil)))))'
+    @echo "--- log tail ---"
+    @tail -3 /tmp/kitty-gfx.log 2>/dev/null || true
+    @rm -f /tmp/kgfx-fake-encoder.sh
+
+# --- Interactive sixel tests (run inside a sixel-capable terminal) ----------
+
+# Open test-image.png with sixel backend forced (foot/Konsole/mintty/WezTerm)
+test-sixel-image encoder="":
+    @echo ">> Run inside foot, Konsole, mintty, mlterm, or WezTerm."
+    TERM={{TERM_}} {{EMACS}} -nw -Q -l {{SRC}} \
+        --eval "(setq kitty-gfx-debug t kitty-gfx-preferred-protocol 'sixel)" \
+        $(if [ -n "{{encoder}}" ]; then echo "--eval (setq\\ kitty-gfx-sixel-encoder-program\\ \"{{encoder}}\")"; fi) \
+        --eval "(kitty-graphics-mode 1)" \
+        tests/test-image.png
+
+# --- Logs -------------------------------------------------------------------
+
 # Tail the kitty-gfx debug log (set kitty-gfx-debug to t to populate)
 log:
     tail -f /tmp/kitty-gfx.log