docs: correct the portable hint-table coverage claims for this fork

docs/fm-test-portable-shards.md

@@ -12,7 +12,8 @@ Local timings are not interchangeable with CI timings: platform and machine load
 Both hint tables were refreshed on 2026-09-30 from five Ubuntu CI runs: [36583881812](https://github.com/kunchenguid/firstmate/actions/runs/36583881812), [36658498535](https://github.com/kunchenguid/firstmate/actions/runs/36658498535), [36663947738](https://github.com/kunchenguid/firstmate/actions/runs/36663947738), [36664663190](https://github.com/kunchenguid/firstmate/actions/runs/36664663190), and [36669175457](https://github.com/kunchenguid/firstmate/actions/runs/36669175457).
 Use the slowest successful `duration_ms` per script across their uploaded portable timing artifacts and completed `FM_TEST_END` log markers, with the two version/platform exceptions below.
 All artifact records were cross-checked against the corresponding job's markers.
-This covers all 24 parallel and 201 serial members; an existing live-capability skip is a portable-runner measurement, not a timing claim for the unavailable live integration.
+Those runs are upstream's, and their records cover all 24 parallel members and the 201 serial members the lane held upstream; an existing live-capability skip is a portable-runner measurement, not a timing claim for the unavailable live integration.
+This fork's serial lane carries additional fork-only members that no upstream run measured, so each of them packs on the `PORTABLE_SERIAL_DEFAULT_WEIGHT_MS` default until the fork refreshes its own hints from its own green CI runs; read the current lane size and unmeasured share from `bin/fm-test-run.sh --check-coverage` rather than from a count copied here.
 Observed maxima provide conservative packing weights, not an upper bound on future durations.
 
 Two serial-5 jobs were cancelled at their 30-minute cap and uploaded no artifact.
@@ -78,7 +79,7 @@ Refresh the CI-derived hints by downloading the per-shard timing artifacts from
 
 ```sh
 for run in <run-id> <run-id> <run-id>; do
-  gh-axi run download "$run" -R kunchenguid/firstmate --dir "/tmp/fm-serial/$run"
+  gh-axi run download "$run" -R <owner>/firstmate --dir "/tmp/fm-serial/$run"
 done
 jq -r '.scripts[] | select(.exit == 0) | [.path, .duration_ms] | @tsv' /tmp/fm-serial/*/fm-test-timing-portable-serial-*/*.json \
   | awk -F'\t' '$2 > m[$1] { m[$1] = $2 } END { for (p in m) print p, m[p] }' \

tests/fm-session-lock-ancestry.test.sh

@@ -765,15 +765,21 @@ test_e2e_background_session_keeps_its_lock_across_a_recycled_chain() {
   grep -qx "$frontend" "$dir/state/phase-1/ancestry" || fail "the healthy chain did not reach the front-end"
   expect_phase_owned "$dir" 1 2 "$frontend" "healthy chain"
 
-  # Recycle the bridge: the daemon ends, the pty-host is reparented to init, and
-  # the front-end that holds the lock stays alive.
+  # Recycle the bridge: the daemon ends, the pty-host is orphaned to whatever
+  # reaper the host uses (init, or a user-session subreaper such as systemd
+  # --user), and the front-end that holds the lock stays alive.
   kill -TERM "$daemon"
   i=0
-  while [ "$i" -lt 200 ] && { kill -0 "$daemon" 2>/dev/null || [ "$(ps -o ppid= -p "$ptyhost" 2>/dev/null | tr -d ' ')" != 1 ]; }; do
+  ptyhost_ppid=$(ps -o ppid= -p "$ptyhost" 2>/dev/null | tr -d ' ')
+  while [ "$i" -lt 200 ] && [ "$ptyhost_ppid" = "$daemon" ]; do
     sleep 0.05
     i=$((i + 1))
+    ptyhost_ppid=$(ps -o ppid= -p "$ptyhost" 2>/dev/null | tr -d ' ')
   done
-  [ "$(ps -o ppid= -p "$ptyhost" 2>/dev/null | tr -d ' ')" = 1 ] || fail "the pty-host was not reparented to init after the daemon ended"
+  kill -0 "$ptyhost" 2>/dev/null \
+    || fail "the pty-host died with the daemon, so the recycled case cannot be exercised"
+  [ "$ptyhost_ppid" != "$daemon" ] \
+    || fail "the pty-host is still parented by the daemon after it ended"
   kill -0 "$frontend" 2>/dev/null || fail "the front-end died with the daemon, so the recycled case cannot be exercised"
 
   # Phase 2: the same session id over the broken chain - the reported drift.

tests/fm-test-run.test.sh

@@ -1754,10 +1754,11 @@ test_herdr_ci_family_run_has_a_step_timeout() {
   # The required Herdr lane's hang tripwire is the family-run *step* bound, not
   # the 75-minute job cap. Parse the workflow as YAML so nested `with.name`
   # artifact keys cannot masquerade as the step contract.
-  command -v ruby >/dev/null 2>&1 \
-    || fail "ruby is required to parse .github/workflows/ci.yml as YAML"
   local json job_timeout step_timeout
-  json=$(ruby -ryaml -rjson -e '
+  # Ruby's YAML is the CI runner's parser; fall back to PyYAML on hosts that
+  # ship python3 without ruby so the contract still runs there.
+  if command -v ruby >/dev/null 2>&1; then
+    json=$(ruby -ryaml -rjson -e '
 doc = YAML.load_file(ARGV[0])
 job = doc.fetch("jobs").fetch("tests-herdr")
 step = job.fetch("steps").find { |s|
@@ -1770,7 +1771,22 @@ puts JSON.generate(
   "step_timeout" => step.fetch("timeout-minutes")
 )
 ' "$ROOT/.github/workflows/ci.yml") \
-    || fail "could not parse tests-herdr timeouts from ci.yml"
+      || fail "could not parse tests-herdr timeouts from ci.yml"
+  elif python3 -c 'import yaml' >/dev/null 2>&1; then
+    json=$(python3 - "$ROOT/.github/workflows/ci.yml" <<'PY'
+import json, sys, yaml
+doc = yaml.safe_load(open(sys.argv[1], encoding="utf-8"))
+job = doc["jobs"]["tests-herdr"]
+step = next(s for s in job["steps"]
+            if isinstance(s, dict)
+            and s.get("name") == "Run real-Herdr family (serial, required)")
+print(json.dumps({"job_timeout": job["timeout-minutes"],
+                  "step_timeout": step["timeout-minutes"]}))
+PY
+) || fail "could not parse tests-herdr timeouts from ci.yml"
+  else
+    fail "ruby or python3 with PyYAML is required to parse .github/workflows/ci.yml as YAML"
+  fi
   job_timeout=$(python3 -c 'import json,sys; print(json.load(sys.stdin)["job_timeout"])' <<<"$json") \
     || fail "could not read job timeout from parsed workflow"
   step_timeout=$(python3 -c 'import json,sys; print(json.load(sys.stdin)["step_timeout"])' <<<"$json") \