journal(conc): P1-P4 evidence (live smokes on cc-ci) + pre-existing abra app ls FATA observation

JOURNAL-conc.md

@@ -22,3 +22,28 @@ Read concurrency-restructure-full-plan.md (SSOT) + plan.md §6.1/§7/§9. Orient
 Working setup: state files on main in this clone; code on branch `restructure/concurrency`
 via a git worktree at ../cc-ci-conc; test runs on the cc-ci host via /root/builder-clone
 (`cc-ci-run -m pytest ...`, `nix develop .#lint`).
+
+## 2026-06-10 — P1–P4 landed on restructure/concurrency
+
+- P1 b492f99: harness/lifetime.py (PDEATHSIG+ppid recheck, SIGTERM/SIGALRM→SystemExit funnel
+  with re-entrancy guard, alarm(3600)); main() installs first; both finally blocks mark
+  begin_teardown(); .drone.yml setsid+trap wrap. Live smoke on cc-ci (cc-ci-run /tmp/p1-smoke.py):
+  TERM→rc=143+finally; ALRM→rc=142+finally+deadline log; parent-kill→child TERM'd, teardown ran.
+- P2 b302f3a: acquire_app_lock + _probe_and_reap + janitor rewrite; registry deleted. Live smoke
+  (/tmp/p2-smoke*.py): held lock → "live concurrent run, leaving it", reaped=[]; killed holder →
+  reap exactly once + lockfile unlinked; waiter blocked during probe-held reap, then re-acquired
+  on the FRESH inode (probe confirmed held by waiter). Note: a select()-on-fd readline artifact
+  in my smoke script initially looked like a failure — kernel state was verified directly.
+  Unlink/recreate race guarded on BOTH sides via fstat/stat st_ino identity checks.
+- P3 17ebdf3: per-run ABRA_DIR. Verified abra CLI honors $ABRA_DIR on-host (skeleton probe:
+  FATAs only on empty servers/; with servers+catalogue symlinks + recipes/ it works and even
+  auto-clones recipes for `app ls` resolution into the per-run dir). p3-smoke: setup + fetch of
+  custom-html-tiny landed in /tmp/p3runs/9999/abra/recipes, head commit + versions readable via
+  abra.recipe_dir(). install_steps.sh path fix justified in DECISIONS.md (conc P3 entry).
+  Pre-existing observation (NOT mine, unchanged): `abra app ls -S -m -n` currently FATAs
+  "unable to resolve '0cc57a5a'" under the DEFAULT abra dir too → janitor's abra discovery
+  yields [] and the docker-service sweep carries discovery. Out of this phase's scope.
+- P4 91d3cc7: concurrency.limit removed; maxTests comment states single-knob + new model.
+  One stale comment line (.drone.yml l.39 "concurrency.limit=2 below") folds into P5.
+
+All four commits: tests/unit 138 passed + lint PASS before each. Next: tests/concurrency suite.