fix(wake): #942 review — force base-10 on the slack knob; shape validation is not radix validation

'08'/'09' pass ^[0-9]{1,9}$ yet are fatal octal in $((...)) — the same
poll-killing mode this PR closes — and '0300' silently means 192, changing the
operator's stated intent with no warning. slack=$((10#$slack)) after the
regex (which guarantees pure digits, so 10# is safe) makes zero-padded knobs
mean what was written instead of rejecting them. Two new D13 sub-cases: '08'
survives with metadata kept, and the discrimination test — '0300' with a ts
+250s ahead KEEPS the ts (decimal 300) where octal 192 would have dropped it.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NsKce8iZuSuRnu3gVMCBKB

packages/mosaic/framework/tools/wake/detector.sh

@@ -301,6 +301,11 @@ _poll_source() {
           echo "detector.sh: WAKE_SNAPSHOT_TS_FUTURE_SLACK='$slack' is not a plain non-negative integer (seconds) — falling back to 300, poll continues (#940)." >&2
           slack=300
         fi
+        # Shape validation is not radix validation: bash reads a leading zero as
+        # OCTAL, so '08'/'09' pass the regex yet are FATAL in $((...)), and
+        # '0300' silently means 192. Force base-10 so the knob means what the
+        # operator wrote (safe: the regex above guarantees pure digits).
+        slack=$((10#$slack))
         now_s="$(date +%s)"
         if [ "$snap_ts" -gt $((now_s + slack)) ]; then
           echo "detector.sh: source '$kind/$id' snapshot_ts is beyond the ${slack}s future-skew allowance (ts=$snap_ts now=$now_s) — snapshot_ts DROPPED, poll continues (#940)." >&2