docs: step-3 rewrites — OQ-39/40 resolved, C-08 closed, channel-operations.md put/control/resources contracts, review 010/011 closed with the S-01 sketch corrected

- open-questions.md: OQ-39 → ADR-052, OQ-40 → ADR-053 (resolutions replace
  the deferred-until-needed posture)
- channel-operations.md: the put contract (initiator allocates + streams,
  reserved input key, one response, acks-in-result sentence), the control
  routing (ADR-052), the enumerator aggregation (ADR-053), the
  connection-owner paragraph's pub-era correction, the ADR table rows
- ADR-051 §6: PubTypedOpen → the put translation; ADR-047's 2026-09-06
  amendment records its era honestly (the dynamic half is now ADR-053)
- review 010: all four findings resolved (with the S-01 sketch correction
  so the published record stops carrying the wrong-graph reading)
- review 011: closed (all seven pins implemented + gates landed)
- review 001 C-08: resolved note (odd/even + adopt, implemented)
- AGENTS.md: the 'Stub Guard' section — the not_implemented grep is part
  of cargo test; the registration invariants and the implement-or-stop
  ruling are release-blocking

Verified: cargo test (696+guard), clippy -D warnings, fmt, doc clean.

docs/architecture/decisions/051-channel-relay-and-hub-leg.md

@@ -205,11 +205,13 @@ same pin.
 
 ### 6. Bounds: rejected shapes and residual notes
 
-- **Pub-typed open ops** — rejected loudly (`channel:pub_open_not_implemented`,
-  the C-08 blocker). The relay registers only `Query`/`Mutation`-typed
-  ops (plain forwarding) and `Sub`-typed marked ops (relay openables);
-  a discovered `Pub`-typed marked spec is an assembly error, not a
-  silent stub.
+- **Pub-typed open ops** — ~~rejected loudly~~ **translated** (ADR-047
+  amendment 4 §4.7 — the put-forwarding translation: the hub allocates
+  its connect-side id, opens the spoke op in the background,
+  pumps the consumer bytes → spoke, and mirrors the spoke's single
+  response with its reserved key stripped; `PubTypedOpen` is removed).
+  The rejection remains for the genuinely-unsupported shapes: unmarked
+  specs (`UnmarkedSpec`) only.
 - **Compounding establishment bounds** — each hop's establisher is
   bounded independently (ADR-049 §2); an N-hop chain adds N bounds.
   The consumer's dispatch deadline (`min(deadline, 10s)` per hop)
@@ -263,7 +265,6 @@ same pin.
   `ChannelRelay` instead of re-deriving the hub shape.
 - U-1's gate 2 (the review's silent-failure scenario — flavor-form ops
   relaying as plain forwarding stubs) becomes a permanent e2e gate.
-
 **Negative:**
 
 - New pub API (`ChannelRelay`, the registration entry point, the