fix(test): generalize awk end-anchor to any ${VAR:?...} (agy P3)

agy follow-up review on PR #159 noted that the awk end-anchor was
coupled to the specific variable name PROJECT_ID. If a future edit
reorders the validation block (e.g. validates REPO before PROJECT_ID)
or renames PROJECT_ID, the extraction would fail to terminate and
the test would silently capture wrapper code beyond the init block.

Generalize the regex to '\${[A-Z_]+:\\?' — matches any uppercase
variable name in the `: "${VAR:?...}"` validation idiom that
the wrappers use to gate startup on required config.

Author: zxkane

tests/unit/test-wrapper-rebind-order.sh

@@ -78,7 +78,11 @@ simulate_wrapper() {
     echo "AUTONOMOUS_CONF='$conf_dir/autonomous.conf'"
     awk '
       /^SCRIPT_DIR=/ { capture = 1; next }
-      /^: "\$\{PROJECT_ID:\?/ { capture = 0 }
+      # End-anchor: any `: "${VAR:?...}"` style validation. Generalized
+      # over a specific name so reordering or renaming the first
+      # validated config var does not silently extend the capture into
+      # the wrapper body. Per agy P3 follow-up review on PR #159.
+      /^: "\$\{[A-Z_]+:\?/ { capture = 0 }
       capture { print }
     ' "$wrapper"
     echo 'echo "AGENT_CMD=$AGENT_CMD"'