docs: the non-custodial migration is complete - every family keyless, server holds zero key material

README, packages/signer/README.md, docs/VECTOR.md, and docs/architecture/non-custodial-split.md
updated for the family-3 (self-improvement) keyless migration - the last of the three families
this migration ever touched:

- README: security notice rewritten as the migration-complete statement (zero tools accept key
  material, every signing operation happens on the local signer, enforced by the now-empty,
  size-zero-pinned custody boundary allowlist); tool count 23 to 24; Self-Improvement Module
  table replaced with browse/analyze plus the four build_* rows, the two-step proposal pair
  marked as two transactions, agent-orchestrated; features and safety copy updated to
  signer-owned spend limits everywhere; Configuration table's three dead spend-limit/audit-log
  rows removed (nothing reads those env vars any more); Safety Layer box removed from the
  architecture diagram entirely (box-drawing alignment verified programmatically, not by eye);
  Testing section names tier-1 vs gated E2E vs LEGACY_FULL for all three keyless families
  including their stake costs.
- packages/signer/README.md: pairing-status bullet and closing line rewritten - all four
  families are keyless now, this signer is the single signing point, nothing is left open.
- docs/VECTOR.md: four new tool sections for the self-improvement build_* family (this doc never
  documented self-improvement under any name before, so these are additions, not renames - same
  situation as the registry family in the prior PR's docs task); Safety Controls section's
  custodial-family list corrected to reflect that none remain.
- docs/architecture/non-custodial-split.md: family-3 landed marker on the PR-sequence table,
  plus the four content-alignment fixes pre-assigned to this PR by
  rehaul-handoff-2026-07-30-content-alignment.md (the "governance" to "self-improvement" renames
  in the two-step-flow heading, the "last family" sentence, the family table label, and the
  rollout row), plus the "Float -> bigint amount math" wording fix.
- .env.example: verified Task 5's edit already states the migration-complete scope correctly
  with a pointer to packages/signer/README.md; no further change needed.

Content rules followed for all new copy in this commit: no "governance" (GOV_* env-var names
exempted, pre-existing deployed config keys), no em dashes, no "funds", research-themed
examples where new examples were needed. Caught and fixed one self-introduced violation before
committing: docs/VECTOR.md's four new tool sections initially copied the file's own pre-existing
em-dash-based parameter-bullet convention; replaced with colons in exactly those new lines,
verified zero em dashes remain in the added range.

docs/architecture/non-custodial-split.md

@@ -121,7 +121,7 @@ interface Policy {
 
 **Accepted trade-off of the 4-call shape:** the signer records **intent to spend** at signing time, not confirmed submission. If a submit later fails, the audit log over-counts. Conservative, therefore acceptable — and it is the price of the signer having no network access. Documented, not hidden.
 
-### Two-step governance flow
+### Two-step self-improvement flow
 
 `submit_proposal` is a lock-then-spend pair with a confirmation wait between. Keyless, that orchestration becomes explicit:
 
@@ -130,7 +130,7 @@ build_self_improvement_proposal_lock → sign → submit → await_transaction
   → build_self_improvement_proposal_spend(lockTxHash) → sign → submit
 ```
 
-This is why governance is the last family: the LLM must drive a stateful, multi-transaction sequence.
+This is why self-improvement is the last family: the LLM must drive a stateful, multi-transaction sequence.
 
 ## 7. Tool inventory
 
@@ -142,7 +142,7 @@ This is why governance is the last family: the LLM must drive a stateful, multi-
 | Build — tx (3) | `build_send_apex`, `build_send_tokens`, `build_transaction` |
 | Build — contracts (2) | `build_deploy_contract`, `build_interact_contract` |
 | Build — registry (5) | `build_register_agent`, `build_update_agent`, `build_transfer_agent`, `build_deregister_agent`, `build_message_agent` |
-| Build — governance (4) | `build_self_improvement_proposal_lock`, `build_self_improvement_proposal_spend`, `build_self_improvement_critique`, `build_self_improvement_endorse` |
+| Build — self-improvement (4) | `build_self_improvement_proposal_lock`, `build_self_improvement_proposal_spend`, `build_self_improvement_critique`, `build_self_improvement_endorse` |
 | Chain ops (2, new) | `submit_transaction`, `await_transaction` |
 
 **Signer — 4 tools, holds the key.**
@@ -190,7 +190,7 @@ TDD throughout: failing test before implementation, every PR.
 | **5** | Builder hardening: auth (enforced when configured), per-identity rate limits, `submit_transaction`, `await_transaction` | no |
 | **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 — governance keyless.** Plus env-driven ref-UTxO config and a CBOR encoding fix | yes |
+| **8** | **Family 3 — self-improvement keyless.** Plus env-driven ref-UTxO config and a CBOR encoding fix ✅ **(landed — this PR)** | yes |
 | **9** | Mainnet cutover: README, security-page correction, deliberate `workflow_dispatch` | — |
 
 **PR 4 is the review that matters.** It is additive, self-contained, and *is* the security boundary. It breaks nothing while it is reviewed.
@@ -207,7 +207,7 @@ TDD throughout: failing test before implementation, every PR.
 | D | `min(1)` APEX floor → real dust floor |
 | E | Endpoint URLs in error text |
 | F | SSE → Streamable HTTP |
-| G | Float → bigint money math |
+| G | Float → bigint amount math |
 | H | Dependency updates |
 
 ### Dependency graph