docs(asset-leasing): drop the contradictory 'non-custodial escrow' claim

The previous wording said 'The program acts as a non-custodial
escrow' and then immediately described the program taking custody
of A tokens in a program-owned vault. Both can't be true.

What's actually true: the program holds funds in vaults during the
lease, the program-derived address signs all transfers, no admin
key exists, and the rules are the deployed bytecode. Reworded to
state this directly without the 'non-custodial' label, which in
common DeFi usage means 'no admin can pull funds outside the rules'
- a much narrower claim than 'the program never touches your funds',
which is what the original phrasing sounded like.

Author: Edward (OpenClaw)

defi/asset-leasing/anchor/README.md

@@ -97,7 +97,12 @@ deadline has passed, and the short seller hasn't returned the tokens -
 in which case the holder seizes the entire collateral as compensation
 for the missing tokens.
 
-The program acts as a non-custodial escrow. It:
+The program acts as the escrow agent. Both the leased tokens and
+the collateral sit in program-owned vaults during the lease, and the
+program-derived address signs all the transfers in and out. There is
+no admin key and no off-program logic that can move funds: every
+transfer is dictated by the rules below, and those rules are the
+deployed bytecode. Specifically:
 
 1. Takes the holder's A tokens and locks them in a program-owned
    vault until a short seller shows up.