docs(wiki): capture session-inbox-monitor received-msg FP as concept

New page concepts/session-inbox-monitor-received-msg-fp.md — sibling of
delegate-task-negative-trigger-fp. Same FP family, new dimension: the carve-out
is already literal+routed (NOT for handling a received message ->
inter-session-peer-discipline) but the route target is not installed, so it has
no competitor and the nearest in-domain skill wins anyway. Borderline (neg 2/3,
EN twin clean), self-corrects on body-load. Bidirectional cross-link +
index + log. New principle: a routed negative competes only if its route
target is installed. Captured in the wiki (not private memory) per owner direction.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.wiki/concepts/delegate-task-negative-trigger-fp.md

@@ -1,7 +1,7 @@
 ---
 title: delegate-task — literal negative triggers beat abstract carve-outs
 type: concept
-updated: 2026-06-09
+updated: 2026-06-17
 ---
 
 # delegate-task — literal negative triggers beat abstract carve-outs
@@ -57,3 +57,7 @@ skill's domain, an abstract "does NOT apply when…" clause is too weak. Put the
 colliding negative phrase** in the description with an explicit **→ <sibling-skill>** route.
 Literal beats abstract under the 1%-rule. See also [[tdd-criteria-design]] for another
 "make the bright line literal, not a judgement call" pattern.
+
+See [[session-inbox-monitor-received-msg-fp]] for the next clause: a literal+routed negative
+still fails if its **route target isn't installed** — the carve-out then has no real competitor
+and the nearest in-domain skill wins anyway.