feat: add Obsidian Exchange

[dak-agent]

Adds a mainnet listing for Obsidian (app.obsdn.trade), a perpetuals exchange on Monad for trading crypto, equity, and ETF perps with leverage.

• File: mainnet/obsdn.jsonc
• Name: OBSDN
• Category: DeFi::Perpetuals / Derivatives
• Links: project https://app.obsdn.trade, X @obsdntrade (verified)

Contracts (Monad mainnet)

Contract	Address
Obsdn (main entry point)	0x90c3747cd4E6bC6FbebB1b3C54D99737590eBE45
SpotLedger (token balances)	0x8d156514dE27823436212bFcA3064Ba1e5236723
PerpLedger (perpetual positions)	0x336Ed437845b6Fae4Ad2d41969e43C470aCfC59C
Matching (order matching engine)	0x227adD7CDe4E7996D9f02975CC16212f19664C03
VaultManager (vaults)	0xedF8C3913CAcB04474e7df06F8c264C269C4591B
AccessControl (roles & permissions)	0x8dbb546BaFDeac0a26095cF8C671D3C96a4DA77d
ContractAddressSigValidator (signature verification)	0x823f7911676963207393C2A67F2b72AeB7888bba
DlnDepositAdapter (cross-chain deposits via deBridge DLN)	0x871904e21Eb9B3d6E415f75EA388553c7e86Fab3

Validated locally with python scripts/validate_protocol.py --network mainnet (passes; no address collisions or canonical-contract inclusions). All 8 addresses verified on-chain.

[github-actions]

Contract Verification Results

Changed Files

• mainnet/obsidian_exchange.jsonc

Verification Output

Verifying 1 protocol file(s)...

  ✓ Obsidian Exchange (8 addresses)

================================================================================
                         CONTRACT VERIFICATION RESULTS                          
================================================================================

✓ Obsidian Exchange (obsidian_exchange.jsonc)

================================================================================
                                    SUMMARY                                     
================================================================================
  Files Processed:     1
  Addresses Checked:   8
  ✓ Verified:          8
  ✗ Not Verified:      0

  All contracts verified successfully!
================================================================================

---

_{Workflow run: Verify PR Contracts}

[github-actions]

Contract Verification Results

Changed Files

• mainnet/obsdn.jsonc

Verification Output

Verifying 1 protocol file(s)...

  ✓ OBSDN (8 addresses)

================================================================================
                         CONTRACT VERIFICATION RESULTS                          
================================================================================

✓ OBSDN (obsdn.jsonc)

================================================================================
                                    SUMMARY                                     
================================================================================
  Files Processed:     1
  Addresses Checked:   8
  ✓ Verified:          8
  ✗ Not Verified:      0

  All contracts verified successfully!
================================================================================

---

_{Workflow run: Verify PR Contracts}