feat: suppress continuation-URL prompt for manifest-listed pkgs; release v1.2.4v1.2.4

On a primary version bump of a manifest-listed package, mkhint used to
prompt interactively for each extra DOWNLOAD (continuation) URL, then
Phase 2 (reconcile_bundle_deps) rewrote those same lines from the
upstream manifest — a pointless double-touch (13 prompts for neovim).

update_hint_file now detects a listed package and threads a skip_cont
flag through update_checksums -> _process_download_var, which leaves the
continuation URLs for the manifest reconcile and prints a short notice
instead of prompting. Non-listed packages prompt exactly as before.

Also fixes a set -e abort: the manifest-lookup guard was written as
`pkg_has_manifest ... && _skip_cont=1`, whose false result (non-listed
package) killed the run right after the backup. Rewritten as an if. This
would have broken every non-listed --hintfile -V update. Verified live on
a non-listed multiline package (exploitdb).

Tests: T-BM18 now asserts the listed-pkg suppression, T-BM25 guards
against over-suppression (non-listed still prompts); the read -p prompt
is invisible under piped stdin, so both assert on the always-echoed
"line N (current)" header. 184 passed.

Also defers the multi-file split TODO with a rationale and revisit
triggers (extract only the bundled-dep block when the time comes).

Bump MKHINT_VERSION and man title to 1.2.4, rebuild mkhint.1.gz.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 0 insertions, 0 deletions

diff --git a/mkhint.1.gz b/mkhint.1.gz
index cf7295c..37815c5 100644
--- a/mkhint.1.gz
+++ b/mkhint.1.gz