build_sha1sums: write sha1sums.txt LF (CRLF trips line-based consumers)

punk-runtime's bash payload reads sha1sums names via bash read, which
keeps a CRLF file's trailing \r (msys grep strips it in text mode) -
a locally-present runtime then also showed as a remote-only row.
Future rewrites emit LF like platforms.txt/defaults.txt; existing
files re-emit on their next content change.

Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com

src/build_sha1sums.tcl

@@ -81,6 +81,9 @@ proc do_sha1_in_folder {binaryfolder level} {
     if {[dict size $existing_sha_dict] != [dict size $new_sha_dict] || $changes > 0} {
         puts stderr "${indent}rewriting sha file at $shafile"
         set fd [open $shafile w]
+        #LF: CRLF sha1sums trip line-based consumers (punk-runtime's bash payload
+        #reads names with a trailing \r; msys grep strips it, bash read does not)
+        fconfigure $fd -translation lf
         dict for {h f} $new_sha_dict {
             puts -nonewline $fd "$h *$f\n"
         }