fix(ci): detect-changes.sh always emits outputs (kill the cascade)

detect-changes used set -e; an aborting git/grep killed it before writing GITHUB_OUTPUT -> the job outputs mapping evaluated to %!t(string=) and failed detect-changes + every job that needs it. Drop set -e, treat base/diff failure as rebuild-all, add an EXIT trap that emits rebuild-all + exit 0 on any early exit. Verified locally: empty/unreachable BASE_SHA + real diff all emit a full 11-key set.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/detect-changes.sh

@@ -2,16 +2,23 @@
 # Emit per-service + aggregate change flags for the CI / build workflows.
 #
 # Reads:
-#   BASE_SHA — diff base. Empty / unreachable → emit everything as true.
+#   BASE_SHA — diff base. Empty / unreachable / diff-failure → emit everything as true.
 #   HEAD_SHA — diff target. Defaults to HEAD.
 #
 # Writes key=value lines to $GITHUB_OUTPUT (defaults to /dev/stdout for local runs).
 #
+# ROBUSTNESS CONTRACT: this script must ALWAYS emit a full set of outputs. A
+# missing/empty output makes the job's `outputs:` mapping evaluate to a Go format
+# error (`%!t(string=)`) which fails detect-changes AND every job that `needs` it
+# (cascade). So we do NOT use `set -e` (an aborting git/grep must not kill the
+# script before it emits), we treat any base/diff failure as "rebuild all", and an
+# EXIT trap emits rebuild-all + forces exit 0 if we ever exit early/unexpectedly.
+#
 # Keys emitted:
 #   admin, backend, sdk, portal, tts, crawler, dsms_gateway, dsms_node
 #   any_python, any_node, any
 
-set -euo pipefail
+set -uo pipefail
 
 BASE_SHA="${BASE_SHA:-}"
 HEAD_SHA="${HEAD_SHA:-HEAD}"
@@ -31,17 +38,27 @@ emit_all_true() {
   done
 }
 
+# Safety net: never let the job end with undefined outputs. If we exit before
+# DONE=1 (any error / early termination), emit rebuild-all and exit 0 so the
+# step still succeeds — rebuild-all is the safe over-approximation.
+DONE=0
+trap '[ "$DONE" = 1 ] || emit_all_true "safety-net (unexpected exit)"; exit 0' EXIT
+
 if [ -z "$BASE_SHA" ]; then
   emit_all_true "no BASE_SHA provided"
-  exit 0
+  DONE=1; exit 0
 fi
 
 if ! git rev-parse --verify "${BASE_SHA}^{commit}" >/dev/null 2>&1; then
   emit_all_true "BASE_SHA ${BASE_SHA} unreachable"
-  exit 0
+  DONE=1; exit 0
+fi
+
+if ! changed=$(git diff --name-only "$BASE_SHA" "$HEAD_SHA" 2>/dev/null); then
+  emit_all_true "git diff against ${BASE_SHA} failed"
+  DONE=1; exit 0
 fi
 
-changed=$(git diff --name-only "$BASE_SHA" "$HEAD_SHA" || true)
 echo "Changed files since ${BASE_SHA}:"
 echo "${changed:-(none)}"
 echo "---"
@@ -91,3 +108,5 @@ else
   emit any false
   echo "  any: false"
 fi
+
+DONE=1