Issue 133/auditor staking

[binayyub4211]

closes #133

What was done: Implemented an economic security layer for the Milestone Oracle network:

Staking Management: Added

set_staking_config
,

deposit_stake
,

request_unstake
, and

withdraw_stake
functions.
Lockup Period: Enforced a configurable lockup period for unstaking requests to prevent malicious exit immediately after voting.
Voting Safeguard: Integrated a check in the

vote
function to ensure auditors meet the minimum staking requirement.
Persistence: Used persistent storage for tracking auditor stakes and pending unstake requests.
Why it was done: To provide economic security for the decentralized oracle system, ensuring auditors have a financial stake that prevents sybil attacks and dishonest behavior during milestone verification.

How it was verified:

Added unit tests in

milestone-oracle/src/lib.rs
covering stake deposits, vote validation (minimum stake check), and lockup enforcement (using ledger timestamp manipulation).
Manual code review for access control and transaction safety.

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[gabito1451]

@binayyub4211 PLEASE look in to the ci fail

[gabito1451]

please resolve conflicts