Audit Build framework and verification code examples

[snissn]

Parent tracker: #65
Linear: GER-639
Base PR: filecoin-project#2457
Base branch: upstream/docs-ia-refresh

Goal

Audit and fix runnable framework and verification examples in the Build section.

Scope

• build/development-frameworks/hardhat.md
• build/development-frameworks/foundry.md
• build/development-frameworks/remix.md if code/example correctness needs minor edits
• build/verification/hardhat.md
• build/verification/foundry.md
• build/verification/blockscout.md
• build/verification/filfox.md

Current Evidence

• The Foundry guide has a bad clone URL using a GitHub /tree/main.git path.
• The Hardhat guide contains older transcript-style output and a hardhart.org typo.
• Verification snippets need to be checked against current Hardhat/Foundry verifier command requirements, Blockscout URLs, Filfox verifier package, chain IDs 314 and 314159, and environment prerequisites.

Completion Criteria

• Clone/install/setup commands point to current maintained repositories and work as shell commands.
• Private key/funded-wallet/RPC requirements are explicit and not hardcoded.
• Verification commands include the network, verifier, chain ID/RPC, and constructor-argument expectations needed to run them.
• Output transcripts are removed, shortened, or labeled as example output if not stable.
• PR is docs-only and based on upstream/docs-ia-refresh.
• PR body includes test evidence, including npm run build or exact reason it was not run.

Non-Goals

• Do not perform a live deployment or require funded-wallet validation.
• Do not merge the PR without human review.