fix(devtag-guard): snapshot explicit VERSION at source time (#194 finding)

The guard read $VERSION, but app bodies set VERSION to the derived default
before calling it, so accidental local --publish without an explicit version
or v* tag still pushed. Capture PARITY_VERSION_EXPLICIT at source time and
gate on that instead.

CHANGELOG.md

@@ -7,6 +7,13 @@ semantic versioning; the version is a conceptual tag (no git tag is created).
 
 ## Unreleased
 
+- **Fix (safety): dev-tag guard was ineffective.** Every publish app body runs
+  `VERSION="$(parity_derive_version <default>)"` before `parity_devtag_guard`, so
+  by the time the guard checked `$VERSION` it was always non-empty (the derived
+  default) and an accidental local `--publish` with no explicit version and no
+  `v*` tag still pushed (cluster #194 finding). The guard now reads a source-time
+  snapshot `PARITY_VERSION_EXPLICIT` captured before any clobber, so it correctly
+  blocks unless the caller set `$VERSION` or `$CI_COMMIT_TAG` matches `^v[0-9]`.
 - `pipeline-doctor` (cluster #191 security sweep): added a scoped per-file check
   asserting **no `set -x` in token-bearing `ci/*.sh` scripts** going forward — a
   script that references a registry token (`REGISTRY_TOKEN` / `CI_REGISTRY_TOKEN`

ci/parity-lib.sh

@@ -22,6 +22,15 @@ PARITY_REGISTRY_OWNER="${PARITY_REGISTRY_OWNER:-oleks}"
 # Local on-disk stage. BUILD-parity artifacts land here; push-staged replays them.
 PARITY_STAGE_DIR="${PARITY_STAGE_DIR:-${PWD}/.parity-stage}"
 
+# Snapshot whether the caller set $VERSION EXPLICITLY, captured at source time —
+# BEFORE any app body overwrites VERSION with the derived default version
+# (VERSION="$(parity_derive_version <default>)"). parity_devtag_guard reads this
+# snapshot, not the live $VERSION, so an accidental local `--publish` with no
+# explicit version and no v* tag is still blocked instead of silently shipping
+# the flake's default version. Set-once: re-sourcing won't clobber the capture.
+: "${PARITY_VERSION_EXPLICIT=${VERSION:-}}"
+export PARITY_VERSION_EXPLICIT
+
 # ---------------------------------------------------------------------------
 # Token resolution: $REGISTRY_TOKEN -> `pass` fallback -> named hard fail.
 # Prints the token on stdout so a caller can `tok="$(parity_resolve_token)"`.
@@ -75,7 +84,9 @@ parity_derive_version() {
 # the flake's default development version.
 # ---------------------------------------------------------------------------
 parity_devtag_guard() {
-	if [ -n "${VERSION:-}" ]; then
+	# Read the source-time snapshot, NOT the live $VERSION (which the app body
+	# has already set to the derived default by the time this runs).
+	if [ -n "${PARITY_VERSION_EXPLICIT:-}" ]; then
 		return 0
 	fi
 	if printf '%s' "${CI_COMMIT_TAG:-}" | grep -Eq '^v[0-9]'; then