docs: wallet/tx family is keyless - security notice, tool tables, spend-limit scope

README, .env.example, and docs/architecture/non-custodial-split.md updated for
the family-1 keyless migration (build_* tools, no mnemonic parameters): custody
notice rewritten to describe the keyless boundary precisely, tool tables synced
to the 23-tool surface (4 renames, 4 changed in place, 2 removed), self-hosting
and testing copy updated, .env.example spend-limit scope annotated, and the
architecture doc's PR-sequence table marks family 1 as landed.

docs/VECTOR.md (flagged by Task 4 as referencing stale tool names) is also
updated: renamed/removed tool sections corrected, keyless changeAddress params
added, and the Safety Controls / Error Handling sections stop claiming
server-side spend limits and mnemonic requirements that no longer apply to the
tools this page documents. Edits confined to tool names and custody claims -
no restructuring, no wholesale ADA to AP3X pass beyond the sections touched.

.env.example

@@ -8,6 +8,10 @@ VECTOR_SUBMIT_URL=https://submit.vector.testnet.apexfusion.org/api/submit/tx
 VECTOR_EXPLORER_URL=https://vector.testnet.apexscan.org
 
 # Safety Limits (in lovelace, 1 ADA = 1,000,000 lovelace)
+# Scope note (non-custodial migration): the keyless build_* family ignores these -
+# spend limits for it are enforced by the LOCAL signer, per user. These server-side
+# limits still govern the remaining custodial families (agent registry,
+# self-improvement) and will be removed when those families go keyless.
 VECTOR_SPEND_LIMIT_PER_TX=100000000             # 100 ADA per transaction
 VECTOR_SPEND_LIMIT_DAILY=500000000              # 500 ADA daily limit