ci: cover Debian 13 and Ubuntu 22.04 in the deb-install matrix

The GitHub deb-install matrix ran debian12/ubuntu24/ubuntu26, but the
local harness (testing/deb-install/test.sh) runs five distros. Add the
missing debian13 (trixie) and ubuntu22 legs so the cloud gate covers the
same distro set as local CI. Each new leg invokes the existing test.sh
scenario, so per-distro behavior is identical to the local run.

Update the granularity-only parity notes in ci.yml, ci-local.sh, and
check-ci-parity.sh to list the full distro set.

.github/workflows/ci.yml

@@ -40,9 +40,9 @@ env:
 #
 # Granularity-only differences (same coverage, different matrix shape —
 # NOT a divergence):
-#   deb-install    — split here into per-distro legs (debian12/ubuntu24/
-#                    ubuntu26) for parallelism; local runs all distros in one
-#                    suite.
+#   deb-install    — split here into per-distro legs (debian12/debian13/
+#                    ubuntu22/ubuntu24/ubuntu26) for parallelism; local runs the
+#                    same distro set in one suite.
 #   dns-resolver   — single leg here; runs all scenarios (same as local).
 # ─────────────────────────────────────────────────────────────────────────────
 
@@ -454,6 +454,12 @@ jobs:
           - suite: deb-install-debian12
             type: deb-install
             scenario: debian12
+          - suite: deb-install-debian13
+            type: deb-install
+            scenario: debian13
+          - suite: deb-install-ubuntu22
+            type: deb-install
+            scenario: ubuntu22
           - suite: deb-install-ubuntu24
             type: deb-install
             scenario: ubuntu24

testing/check-ci-parity.sh

@@ -13,9 +13,9 @@
 #
 # Granularity-only differences folded before comparison (same coverage,
 # different matrix shape — NOT a divergence):
-#   deb-install    — GitHub splits into per-distro legs
-#                    (deb-install-debian12/ubuntu24/ubuntu26); local runs all
-#                    distros in one suite. Folded to "deb-install".
+#   deb-install    — GitHub splits into per-distro legs (deb-install-debian12/
+#                    debian13/ubuntu22/ubuntu24/ubuntu26); local runs the same
+#                    distro set in one suite. Folded to "deb-install".
 #   chaos-*        — GitHub fans each chaos scenario into its own matrix leg
 #                    (type: chaos); local runs them all via the one CHAOS_SUITES
 #                    path. The individual scenario names also differ cosmetically

testing/ci-local.sh

@@ -50,7 +50,8 @@
 # Granularity-only differences (same coverage, different matrix shape —
 # NOT a divergence):
 #   deb-install    — local runs all distros sequentially in one suite; GitHub
-#                    splits into per-distro legs (debian12/ubuntu24/ubuntu26).
+#                    splits into per-distro legs (debian12/debian13/ubuntu22/
+#                    ubuntu24/ubuntu26 — the same distro set).
 #   dns-resolver   — single suite both sides; runs all scenarios.
 # ─────────────────────────────────────────────────────────────────────────────
 set -uo pipefail