[v0.2.0] README: add common-recipes section

[neverDefined]

Problem

The README explains what go-anvil is but doesn't show common end-to-end patterns. New users have to piece together calls from godoc.

Proposal

Add a "Recipes" section after the Quick Start with 4-6 short, copy-pasteable snippets. Pull these from the godoc Example functions in #70 so they stay in sync (or vice versa — link from README to godoc Examples).

Suggested recipes:

1. Fund a fresh account — NewFundedAccount (depends on [v0.2.0] Wallet helpers: FundAccounts and NewFundedAccount #56).
2. Time-travel a block timestamp — AdvanceTime (depends on [v0.2.0] Time-travel ergonomics: AdvanceBlocks and AdvanceTime #57).
3. Snapshot, mutate, revert — Snapshot/Revert pattern.
4. Fork from mainnet — WithFork + WithForkBlockNumber.
5. Impersonate a whale — Impersonate + SetBalance.
6. Trace a failing tx — DebugTraceTransaction (depends on [v0.2.0] Add debug_traceTransaction and debug_traceCall wrappers #58).

Each recipe: 8-12 lines, no error handling boilerplate (use must style or just _, _ = ... for brevity, with a comment noting the user should handle errors in real code).

Acceptance criteria

• Recipes section in README.
• Cross-link between README and pkg.go.dev godoc Examples.
• Recipes don't drift from real code — either they're copied from the Example functions, or there's a CI check that they compile (e.g. go run a sample file).