feat: add swidge (swap/bridge) via LI.FI SDK

[arein]

Summary

• New companion-wallet swidge CLI operation for manual cross-chain bridging powered by @lifi/sdk
• Auto-bridge in sendTransaction() — detects insufficient funds and bridges from another chain (prompts in TTY, auto-bridges in pipe/agent mode)
• Pre-flight balance warning in WalletConnect CLI send-transaction for EVM chains
• Supports ETH, USDC, WCT across Ethereum, Base, and Optimism

Demo: Bridge ETH from Optimism to Base

companion-wallet swidge \
  --from-chain eip155:10 --to-chain eip155:8453 \
  --from-token eth --to-token eth --amount 0.0001

{"fromChain":"eip155:10","toChain":"eip155:8453","fromToken":"ETH","toToken":"ETH","fromAmount":"0.0001","toAmount":"0.000099614025","txHash":"0xa4f1746c..."}

New files

File	Purpose
packages/companion-wallet/src/swidge.ts	Core swidge module
packages/companion-wallet/test/swidge.test.ts	16 unit tests
.changeset/swidge-feature.md	Minor version bump changeset

Key changes

File	Change
companion-wallet/package.json	Added @lifi/sdk dependency
companion-wallet/src/types.ts	Swidge types + "swidge" operation
companion-wallet/src/chains.ts	resolveChainByNumericId()
companion-wallet/src/tokens.ts	getLifiTokenAddress(), findTokenSymbolByAddress()
companion-wallet/src/prompt.ts	Exported ask() with configurable output stream
companion-wallet/src/rpc.ts	Auto-swidge check before sendTransaction()
companion-wallet/src/cli.ts	handleSwidge() handler
cli-sdk/src/cli.ts	Non-blocking balance warning

Test plan

• Build passes (npm run build)
• All 235 tests pass (npm run test)
• Lint clean (npm run lint)
• Manual test: bridged 0.0001 ETH from Optimism → Base successfully
• Manual test: companion-wallet swidge USDC Base → Optimism (needs gas on Base)
• Manual test: auto-bridge triggered via send-transaction on underfunded chain

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