[codex] add calldata decoder

[alextnetto]

Summary

• Adds a server-side calldata decoder that prefers verified contract ABIs, falls back to public selector databases, and returns normalized JSON for decoded calls, ambiguity, invalid calldata, native transfers, and unknown selectors.
• Adds a /api/calldata/decode route and React Query hook, then renders decoded action details on draft pages while keeping raw target/value/selector/calldata visible.
• Splits the draft detail route into a server wrapper plus client component so metadata and draft detail rendering can coexist, and adds OG metadata helpers/assets for draft links.
• Fixes existing React Compiler lint issues in the new draft form and action builder by removing render-time timestamp/state synchronization patterns.

Notes

• extraData is accepted by the decoder API but intentionally not trusted as an ABI source yet; persisted ABI hints should be a follow-up once the gas/user-data tradeoff is settled.
• ETHERSCAN_API_KEY is optional. Without it, decoding still falls back to selector database candidates.

Validation

• pnpm --filter web lint
• pnpm --filter web build
• pnpm -r --if-present build
• forge test
• pnpm test:e2e
• Smoke-tested /api/calldata/decode with an encoded ERC20 transfer(address,uint256) payload.
• Smoke-tested /new in Playwright with no console errors.