refactor(chain): return named parameter structs from tBTC getters

[piotr-roslaniec]

Summary

The on-chain tBTC parameter getters returned wide positional tuples that
callers destructured with long blank-identifier lists. For example:

_, _, _, _, _, _, _, sweepTxMaxTotalFee, _, _, _, err := chain.GetMovingFundsParameters()

GetMovingFundsParameters returned 11 values plus err. Because many of the
values share a type, a positional slip in one of these lists compiles cleanly
and fails silently at runtime.

This replaces the wide tuples with named structs in pkg/tbtc, so callers
access fields by name:

movingFundsParameters, err := chain.GetMovingFundsParameters()
... movingFundsParameters.SweepTxMaxTotalFee ...

Changes

• New pkg/tbtc/parameters.go defining MovingFundsParameters,
  WalletParameters, DepositParameters, RedemptionParameters.
• GetMovingFundsParameters (on tbtc.BridgeChain, embedded by tbtcpg.Chain)
  and the three others (on tbtcpg.Chain) now return the corresponding struct.
• All structs live in pkg/tbtc, which both the ethereum adapter and tbtcpg
  already import, so no new dependency edges are introduced.
• Updated the ethereum adapter implementations, three inline-interface
  declarations in pkg/tbtc/moving_funds.go, both local test chains (which get
  simpler — their internal struct aliases are dropped), and all call sites.

Net: the diff removes more than it adds; the change is a simplification.

Notes for review

• Each of the call-site conversions was mapped position-by-position against the
  original tuple order, and the tbtcpg tests discriminate a wrong-but-
  same-typed field pick (e.g. moved_funds_sweep sets TxMaxTotalFee to 0 but
  SweepTxMaxTotalFee to a non-zero value).
• pkg/tbtc's test-only localChain.GetWalletParameters is left as the old
  wide-tuple panic("unsupported") stub. It satisfies no tbtc interface (only
  tbtcpg.Chain declares GetWalletParameters), so it is dead in the tbtc
  package and was left untouched to keep the change surgical.

Verification

• go build ./... and go vet ./... clean.
• pkg/tbtc, pkg/tbtcpg, and pkg/chain/ethereum test suites pass.

Summary by CodeRabbit

• New Features

  • Added standardized parameter structures for deposits, redemptions, wallets, and moving funds.
  • Consolidated configuration retrieval into structured results, making fee limits, thresholds, timeouts, and balance settings easier to access.

• Refactor

  • Updated related transaction, sweep, and wallet workflows to use the consolidated parameter structures without changing their existing behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 8d575896-3fdc-4c92-bff6-f556f7948505

📥 Commits

Reviewing files that changed from the base of the PR and between 5245f66 and c4cc0ad.

📒 Files selected for processing (11)

• pkg/chain/ethereum/tbtc.go
• pkg/tbtc/chain.go
• pkg/tbtc/chain_test.go
• pkg/tbtc/moving_funds.go
• pkg/tbtc/parameters.go
• pkg/tbtcpg/chain.go
• pkg/tbtcpg/chain_test.go
• pkg/tbtcpg/deposit_sweep.go
• pkg/tbtcpg/moved_funds_sweep.go
• pkg/tbtcpg/moving_funds.go
• pkg/tbtcpg/redemptions.go

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📝 Walkthrough

Walkthrough

TBTC parameter getters now return shared structs for deposit, redemption, wallet, and moving-funds settings. Interfaces, Ethereum and local implementations, validation logic, and fee-estimation consumers are updated to use the new struct fields.

Changes

TBTC parameter consolidation

Layer / File(s)	Summary
Shared parameter contracts pkg/tbtc/parameters.go, pkg/tbtc/chain.go, pkg/tbtc/moving_funds.go, pkg/tbtcpg/chain.go	Adds exported parameter structs and updates chain interfaces to return consolidated parameter values.
Chain implementations pkg/chain/ethereum/tbtc.go, pkg/tbtc/chain_test.go, pkg/tbtcpg/chain_test.go	Maps bridge results and local test-chain state into the shared parameter structs.
Moving-funds validation pkg/tbtc/moving_funds.go	Reads the moving-funds timeout from the returned parameter struct.
TBTC workflow consumers pkg/tbtcpg/deposit_sweep.go, pkg/tbtcpg/moved_funds_sweep.go, pkg/tbtcpg/moving_funds.go, pkg/tbtcpg/redemptions.go	Updates fee estimation, wallet selection, and redemption handling to access parameter struct fields.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• threshold-network/keep-core#4172: Updates deposit sweep fee-calculation logic in the same consumer file.
• threshold-network/keep-core#4185: Also changes moving-funds safety-margin code.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: tBTC getters now return named parameter structs instead of positional tuples.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/named-chain-param-getters

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[lrsaturnino]

No blocking issues found.