fix: correct vesting schedule boundary and silent ETH transfer failure

[saddam92]

Summary

Two bugs fixed across SmartEscrow and Recovery contracts.

Bug 1 – SmartEscrow: incorrect total vested amount after end

The _vestingSchedule function used OP_TOKEN.balanceOf(address(this)) + released
when timestamp > end. Because the token balance decreases as tokens are released,
this makes releasable() return a progressively lower (and eventually underflowing)
amount, potentially stranding tokens in the contract permanently.

Fixed by computing total vested tokens from immutable schedule parameters only.
Also corrected > to >= to include the exact end timestamp.

Bug 2 – Recovery: silent ETH transfer failure

withdrawETH used if (!success) continue which silently skips failed transfers,
permanently losing ETH with no revert or event emitted.

Fixed by replacing with require(success, ...) to revert the entire batch on failure.

[cb-heimdall]

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