Bundle LBTC and USDC updates with router migration

[kylesmartin]

Plus - skip onRamp update if an onRamp already exists, allow using a different registered pool for Lombard

[Copilot]

Pull request overview

This PR bundles additional token-related updates into the EVM router migration flow (LBTC/Lombard + USDC) and makes Lombard chain configuration more flexible by allowing an explicit token pool ref, while also making on-ramp updates safer by not overwriting an existing on-ramp.

Changes:

• Add RegisteredTokenPoolRef to Lombard chain configuration and plumb it through to the Lombard configure sequence to resolve the pool by an explicit datastore ref when provided.
• Update ConfigureChainForLanes to only set an OnRamp when none is currently set (avoid overwriting).
• Extend the v1.2.0 EVM RouterUpdater to optionally (when relevant contracts exist) set LBTC’s pool in TokenAdminRegistry and update USDC lock/burn mechanisms; add tests for the new routing behavior.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
deployment/v1_7_0/changesets/deploy_lombard_chains.go	Adds optional RegisteredTokenPoolRef to Lombard changeset config and passes it into configuration input.
deployment/v1_7_0/adapters/lombard.go	Extends Lombard configure input struct with RegisteredTokenPoolRef.
ccv/chains/evm/deployment/v1_7_0/sequences/lombard/configure_lombard_chain_for_lanes.go	Resolves Lombard token pool via explicit registered ref when provided, else falls back to qualifier-based lookup.
ccv/chains/evm/deployment/v1_7_0/sequences/configure_chain_for_lanes.go	Avoids overwriting an existing on-ramp (safer router configuration).
chains/evm/deployment/v1_2_0/adapters/router.go	Bundles LBTC TAR SetPool + USDC mechanism updates into router updater when corresponding contracts are present.
chains/evm/deployment/v1_2_0/adapters/router_test.go	Adds coverage for router updater behavior with/without Lombard pool present in datastore.
ccv/chains/evm/deployment/latest/operations/lombard_token_pool/lombard_token_pool.go	Adds GetToken read operation for LombardTokenPool to support TAR SetPool wiring.

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[tt-cll]

one of the tests is failing and looks legit:

=== Failed
=== FAIL: deployment TestMigrateTo1_6_0 (0.32s)
    lane_migrator_test.go:122: 
        	Error Trace:	/home/runner/work/chainlink-ccip/chainlink-ccip/integration-tests/deployment/lane_migrator_test.go:122
        	Error:      	Received unexpected error:
        	            	no adapter registered for chain family evm-1.2.0 and version 1.2.0
        	Test:       	TestMigrateTo1_6_0
        	Messages:   	Failed to apply LaneMigrateToNewVersionChangeset

[github-actions]

Metric	CCIP-9767	develop
Coverage	70.1%	69.8%