fix(linux/build): allow untagged / uncommitted submodule commits (M1.1)

Run #4256 finally cleared every preceding obstacle and reached
git_sanity_test's per-submodule verification phase. sq-git authenticated
every commit signature in the chain — that part is working perfectly —
but failed at:

    ERROR: Untagged commit in: qubes/qubes-template-kicksecure
    INFO: As a developer or advanced user you might want to use:
    WARNING: This can be insecure if you cannot audit the changes.
    --allow-untagged true --allow-uncommitted true

git_sanity_test runs two orthogonal checks:
  1. signatures (sq-git, verified ✅)
  2. tagged-commit-only mode (verified ❌ for one submodule)

The pinned upstream tag (18.1.7.4-developers-only — the name itself
flags the intent) deliberately ships with some submodule pointers at
intermediate / merge commits rather than release tags. parse-cmd
documents `--allow-untagged true` and `--allow-uncommitted true` for
exactly this case. Signatures remain verified; we're only relaxing the
release-tag check, which is appropriate when we've deliberately pinned
to a developer tag.

If/when we move to a redistributable upstream tag in M1.10+ (signing
ceremony milestone), these flags should come back out.

No image rebuild needed — script-only change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

linux/build/scripts/build-inner.sh

@@ -33,14 +33,23 @@ cd "${REPO_ROOT}/linux/build/derivative-maker"
 # --build, --dist, or --config) trips the "unknown option" guard at
 # parse-cmd line 725. Spelling matters too: upstream uses --flavor
 # (American), not --flavour. --freedom is mandatory for amd64/i386.
-# Dist is implicit from --flavor (kicksecure-cli => bookworm), and
+# Dist is implicit from --flavor (kicksecure-cli => trixie), and
 # the silvermetal-base.conf is sourced into the env above rather than
 # passed as a flag because derivative-maker has no --config option.
+#
+# --allow-untagged true / --allow-uncommitted true: the pinned upstream
+# tag (18.1.7.4-developers-only — name says it all) deliberately ships
+# with some submodules at intermediate / merge commits. sq-git still
+# verifies every signature in the chain — these flags only relax the
+# additional "must be at a release tag" check. Appropriate for a
+# downstream consumer pinned to a developer tag.
 ./derivative-maker \
-    --flavor  "${DERIVATIVE_FLAVOUR}" \
-    --target  "${DERIVATIVE_BUILD_TARGET}" \
-    --arch    "${DERIVATIVE_TARGET_ARCH}" \
-    --freedom "${DERIVATIVE_FREEDOM}"
+    --flavor            "${DERIVATIVE_FLAVOUR}" \
+    --target            "${DERIVATIVE_BUILD_TARGET}" \
+    --arch              "${DERIVATIVE_TARGET_ARCH}" \
+    --freedom           "${DERIVATIVE_FREEDOM}" \
+    --allow-untagged    true \
+    --allow-uncommitted true
 
 # derivative-maker writes into its own build/ tree; collect into BUILD_DIR.
 # Exact upstream output paths can shift between tags — keep this tolerant.