docs(remediation): D-7 reaper doctrine into RM-50; adopt board-roll for the LIVE board

D-7 resolution recorded. Mos verified attribution independently and reaped ~5.2G of
dead-session scratch as lead coordinator. The finding is the gap it exposed: the
authority to reap exists, the deterministic reaper does not.

Two doctrine points now binding on RM-50: (1) 'agents should tidy up' is
instructions-are-not-enforcement wearing another hat — a reaper must own it;
(2) refusing to unilaterally delete another session's scratch was correct, and the
fix is mechanically-decidable ownership/liveness, not braver deletion. Reaper
requirements specified: mechanical liveness (not mtime alone), age threshold,
dry-run, audit event per reap — never a heuristic sweep, which would reintroduce
the P-WORKFLOW-001 auto-sync failure in a more destructive form.

Board restructured into an explicit BOARD-ROLL zone and rolled with the framework's
own board-roll.sh (8432B -> 8014B, D-1 archived to BOARD-LEDGER.md) rather than
hand-trimmed. The tool exists precisely to stop coordinators hand-trimming; using it
is the dogfood.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

docs/remediation/TASKS.md

@@ -116,6 +116,27 @@ tmux-session GC.
 **Added to RM-01 as acceptance criteria:** heavy build artifacts (node_modules, package stores, build
 output) must land on the main disk in the worktree, never on the shared 30 G `/tmp`.
 
+**Resolution, and the part that is actually the finding.** Mos verified the attribution independently
+(mtimes, no process or `lsof` holding either path, no live session maps) and reaped both as lead
+coordinator: `/tmp` went to 79%, 6.0 G free. But note _how_ it was resolved — **a human-authority seat
+did it by hand, because the authority exists and the reaper does not.** That gap is the finding, not
+the disk usage.
+
+Two doctrine points fall out, both binding on RM-50:
+
+1. **The fix is not "agents should tidy up."** Asking each seat to clean its own scratch is
+   `instructions are not enforcement` (D-4) wearing a different hat. A deterministic reaper must own
+   it — same conclusion the north star reaches for every other class in this mission.
+2. **Refusing to unilaterally delete another session's scratch was correct, and the resolution is not
+   "be braver about deleting."** An agent guessing that someone else's state is garbage is exactly the
+   unreviewed destructive act the Constitution forbids. The resolution is that _ownership and liveness
+   become mechanically decidable_, so reaping is a determination rather than a judgement call.
+
+**Reaper requirements for RM-50:** liveness determined mechanically (process/`lsof`/session-map, not
+mtime alone); an age threshold; a dry-run that reports what it would reap and why; and an audit event
+per reap. Never a heuristic sweep — that would reintroduce the P-WORKFLOW-001 auto-sync failure in a
+more destructive form.
+
 **The self-erasure is the important part.** An inert gate that is masked by unrelated downstream
 commits produces no lasting artifact, which is precisely why this class survives for months. Detection
 cannot rely on "is `main` currently red" — it must be per-merge-commit.
@@ -237,7 +258,7 @@ spread is itself information, and X1 says we calibrate on real merged PRs.
 
 | id    | task                                                                                                                                                 | src                   | depends_on                 | est (S/O)        | tier   |
 | ----- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------- | -------------------------- | ---------------- | ------ |
-| RM-50 | One roster-owned socket/host; quarantine unmanaged; stale-session GC                                                                                 | O+S                   | RM-04                      | 14K / 150K       | sonnet |
+| RM-50 | One roster-owned socket/host; quarantine unmanaged; **deterministic reaper for stale sessions AND dead-session disk scratch** (D-7)                  | O+S+live              | RM-04                      | 14K / 150K       | sonnet |
 | RM-51 | Auto-sync **allowlist** (never auto-stage unknown paths) + worktree/lease isolation                                                                  | O+S                   | RM-02                      | 8K / 110K        | sonnet |
 | RM-52 | Retire the Python controller + duplicate MACP islands (3 → 1)                                                                                        | O+S                   | RM-26, RM-27, RM-25, RM-28 | 14K / 110K       | codex  |
 | RM-53 | Flat-file orchestration → DB hard cutover, with rehearsed rollback artifact                                                                          | O+S                   | RM-27, RM-30, RM-34, RM-29 | (in S-10) / 200K | opus   |