Merge !1814: distro/pkg/deb: apply most differences from downstream Debian

distro/pkg/deb: apply most differences from downstream Debian

Merge !1822: ci: pkg: updates for Ubuntu 26.04

daemon/http.c nit: fix const-warnings with C23

tests/integration/deckard: updated with fix for pydnstest symlink

.gitlab-ci.yml: updated IMAGE_TAG

.gitlab-ci.yml: use Python 3.14 as default

.python-version: update versions

.gitlab-ci.yml: pkg:make-archive: use Ubuntu 26.04

Merge !1821: nit cleanups, mostly dropping knot_mm_t uses

cache nit: drop unused knot_mm_t* parameter

daemon nit: drop useless struct engine::pool

lib/resolve nit: drop unused struct kr_context::pool

struct kr_query: dissolve ::forward_flags

Merge !1820: Fix outdated docs: files-watchdog -> watchdog