Record task 3.0 rulings (FABRIC-3.5.md §XLVI); close FABRIC-3.6.md task 3.0

Captain Bob ruled all five §XLV.4 sub-items plus task 3.3's heat-cost
design point: ACK on channel-open+delivery only; the channel-open ACL
hook is a new word in ACL.4th; switch-table sizing mirrors Stadium's
stadium_max_vm_count_val; chunks carry (msg_id, seq, is_last); drain
one message per outermost-interpret checkpoint; publish costs one
message per subscriber. Tasks 3.1-3.7 may now be written precisely.

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

FABRIC-3.6.md

@@ -761,11 +761,14 @@ depends on) is the next step, before any Phase 3 code.
 Each is one commit with three-ISA acceptance, per the standing rules. Tasks marked **[needs
 ruling]** cannot be written precisely until Captain Bob settles the named sub-item.
 
-- [ ] **3.0** — **Decision gate, not code.** Rule on the §XLV.4 sub-items: **(a)** ACK cadence
+- [x] **3.0** — **Decision gate, not code.** Rule on the §XLV.4 sub-items: **(a)** ACK cadence
       (advised: channel open + delivery, not every common-channel message); **(b)** where the
       channel-open ACL hook lives in `ACL.4th`; **(c)** the dynamic switch-table sizing rule;
       **(d)** chunk framing; **(e)** drain one message per checkpoint (§XLIII.6.3, recommended,
       never ruled). *Check:* each answer recorded in `FABRIC-3.5.md`.
+      2026-09-21 · no commit (documentation ruling, see `FABRIC-3.5.md` §XLVI) · all five
+      sub-items plus task 3.3's heat-cost point ruled by Captain Bob, all recommended defaults
+      accepted.
 - [ ] **3.1** — **Dynamic switch table** (B2) **[needs ruling 3.0c]**. Read
       `SK_SWITCH_MAX_SLOTS`'s every use first; replace the constant with a boot-time,
       RAM-derived allocation (Stadium's `stadium_max_vm_count_val` pattern). *Check:* boot