FABRIC-3.md §H: close gap #1 -- non-pinned session mapping

Confirmed: an ephemeral user VM's session lands as a non-pinned,
COOL-subject Stadium patron -- synthesized from D.2's earlier finding
(session ending = VM detach, reuse COOL) rather than a fresh decision.
Thumbdrive detach is the explicit trigger. No exception case for a
temporarily-pinned user VM.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

FABRIC-3.md

@@ -3582,9 +3582,15 @@ plan," D's own intro) — nothing here is scoped into implementable items yet.
 - **A session is a Stadium patron** *(Captain Bob, confirming): "Oh, yeah. God. This is...
   this becomes a patron of the stadium, I believe, session, that is."* Pinned patrons are
   exempt from the normal departure path (heat decay / `COOL`) — they never leave.
-- **Open, not yet stated:** whether a *non-pinned* session (an ordinary Stadium patron subject
-  to `COOL`) is where a future ephemeral user VM's session would land. The pinned/patron
-  framing is confirmed; this specific mapping is not — don't assume it.
+- **Resolved 2026-09-02**: yes, a non-pinned session (an ordinary Stadium patron subject to
+  `COOL`) is where an ephemeral user VM's session lands. Synthesized from D.2's earlier
+  finding rather than a fresh decision — D.2 (2026-08-27) already established "ending a
+  session is a VM detach... far closer to the existing, real, working `COOL`/
+  `capsule_vm_kill()` path" for user sessions tied to a thumbdrive; thumbdrive detach is the
+  explicit trigger, not just passive heat decay while idle. Pinned system VMs (Hera, Hermes,
+  Artemis) are permanently exempt from `COOL` regardless of idle state; non-pinned user VMs
+  are exempt from nothing. No exception case (e.g. a user VM temporarily pinned while
+  actively attached) — ruled out, confirmed as-is.
 
 ### H.2 — Session struct shape
 
@@ -3733,9 +3739,10 @@ left ungated.
 
 Explicitly open items surfaced during this capture pass, none decided yet:
 
-1. **Non-pinned session mapping (H.1).** Does an ephemeral user VM's session land as a
-   non-pinned (normal-departure, `COOL`-subject) Stadium patron? Framing confirmed, this
-   specific mapping is not.
+1. **CLOSED 2026-09-02 — non-pinned session mapping (H.1).** Yes — an ephemeral user VM's
+   session lands as a non-pinned, `COOL`-subject Stadium patron, thumbdrive detach as the
+   explicit trigger (synthesized from D.2's earlier finding). No exception case for a
+   temporarily-pinned user VM.
 2. **`parent` and `name` session fields (H.2).** Proposed by the model, never explicitly
    confirmed by Captain Bob — the field list is stated as a live, expected-to-churn draft
    ("we're gonna be revisiting this part of it around and around for a while").