feat: add automated escrow release — anyone can trigger release after a deadline if beneficiary has not claimed

[BigBen-7]

Description

If the organizer loses their key or forgets to claim, funds are permanently stuck. An automated release trigger allows anyone to initiate release after a configurable deadline.

What to do

• Add auto_release_after_ledger: u32 to EscrowRecord
• Add trigger_auto_release(e, caller, escrow_id) to escrow.rs:
  • No auth check — anyone can call
  • Requires e.ledger().sequence() >= escrow.auto_release_after_ledger
  • Releases to beneficiary, emits ("auto_released", escrow_id, caller)
• Expose in contract.rs, add tests

Files touched

• src/escrow.rs
• src/contract.rs
• src/escrow_test.rs

PR requirement

• Closes #[issue_id] — Timeframe: 48 hours