docs: mainnet cutover complete - both hosted instances run the keyless build (deployed 2026-07-31)

David dispatched the mainnet cutover this morning: deploy-mainnet.yml ran successfully at
2026-07-31T11:00:06Z-11:01:20Z, deploying commit 04e410b (the PR #11 merge, itself the tip of
main after PRs #9/#10/#11 all merged 10:39:29Z-10:39:59Z the same morning). Testnet had already
auto-deployed the identical commit at 10:40:01Z-10:41:50Z. The non-custodial migration is now
complete on both hosted instances, not just in the code - the exact moment the prior docs pass's
deliberately-hedged notice was written for.

Verified directly before writing anything, not taken on faith from the dispatch: git/gh confirm
the merge timestamps and that both deploy workflow runs targeted 04e410b exactly; the custody
grep and safety.ts's absence were reconfirmed on this exact commit; both hosted endpoints
(https://mcp.vector.mainnet.apexfusion.org/sse and the testnet equivalent) were probed directly
with a bare curl request and both returned HTTP 401 right now - meaningful evidence on its own,
since the pre-PR#8 image had no auth at all, so a 401 today proves post-migration code is what's
actually running, not just what the deploy logs claim.

- README.md: the deployment-status callout rewritten with the dated, both-networks-current
  facts, replacing the custody caveat with an access caveat - both instances require a bearer
  token from the operators now (an access control, not a custody signal; neither instance would
  accept a mnemonic from an authenticated caller either, since the tool schemas that would carry
  one no longer exist). The connect command now shows the bearer-token header syntax, verified
  against Claude Code's own current `claude mcp add` documentation before writing it (`--transport
  sse` accepts `--header "Authorization: Bearer <token>"`, same as `--transport http`). The
  security notice rescoped from "this codebase, not every deployment" to a dated claim: complete
  in this codebase and on both hosted instances as of the 2026-07-31 cutover deploy specifically,
  explicitly not a "forever" claim - a future deploy is a separate operational action.
- packages/signer/README.md: the two passages scoped to "this codebase" in the prior docs pass
  now scoped to "any instance running the 2026-07-31 deploy or later," mainnet included, with the
  same access-control caveat about the bearer token.
- docs/architecture/non-custodial-split.md: PR-sequence row 9 (mainnet cutover) gets the same
  landed-marker style as rows 6-8, dated; section 11's rollout paragraph gets its one now-historical
  clause corrected to past tense with a dated annotation appended, following the established
  forward-only annotation convention rather than rewriting the paragraph.

Open public access (no token, per-IP rate limiting) remains a planned follow-up, not yet an open
PR or branch - checked directly (gh pr list, git branch -a) rather than assumed, and stated in
the docs as planned, not implied as already in progress.

docs/architecture/non-custodial-split.md

@@ -191,7 +191,7 @@ TDD throughout: failing test before implementation, every PR.
 | **6** | **Family 1 — wallet/tx keyless.** Mnemonics removed; `build_*` tools land ✅ **(landed — this PR)** | **yes** |
 | **7** | **Family 2 — agent registry keyless.** Drops `@ts-nocheck` from `agent-network.ts` ✅ **(landed — this PR)** | yes |
 | **8** | **Family 3 — self-improvement keyless.** Ref-UTxO env config carried over from the custodial code; the suspected CBOR encoding issue closed as no-bug (audit #10, golden-pinned against a live on-chain token) ✅ **(landed — this PR)** | yes |
-| **9** | Mainnet cutover: README, security-page correction, deliberate `workflow_dispatch` | — |
+| **9** | Mainnet cutover: README, security-page correction, deliberate `workflow_dispatch` ✅ **(landed — deployed 2026-07-31)** | — |
 
 **PR 4 is the review that matters.** It is additive, self-contained, and *is* the security boundary. It breaks nothing while it is reviewed.
 
@@ -223,7 +223,7 @@ PR 4 and PR 5 both depend on the workspace split (PR 3) and can proceed in paral
 
 ## 11. Rollout
 
-Testnet auto-deploys on push to `main` (`deploy.yml`) and **is the proving ground** — breaking it from PR 6 onward is expected and useful signal. Mainnet deploys only by manual `workflow_dispatch` and **stays on the last custodial image until PR 9**. This uses the existing CI split as designed; no new infrastructure.
+Testnet auto-deploys on push to `main` (`deploy.yml`) and **is the proving ground** — breaking it from PR 6 onward is expected and useful signal. Mainnet deploys only by manual `workflow_dispatch` and **stayed on the last custodial image until PR 9** ✅ **(cutover deployed 2026-07-31, both networks now run the same image)**. This uses the existing CI split as designed; no new infrastructure.
 
 ## 12. Findings from local verification