[codex] Fix About and Developers docs IA

[its-DeFine]

Summary

This PR cleans up the public About and Developers docs surface on docs-v2-dev after a dedicated QA pass in a fresh PC2 VM.

Main changes:

• removes duplicated/draft public navigation such as Developers2, deprecated protocol2/network2 groups, empty groups, zero-byte pages, and malformed entries
• fixes rooted internal links in the public About/Developers surface
• normalizes remaining public About/Developers pages to status: current
• quarantines command-heavy or externally keyed pages from public nav until they can be validated with real credentials/service state
• fixes invalid pasted IA text in jsconfig.json
• excludes v2/developers2/** from Mintlify scanning via .mintignore
• rewrites the local testnet guide around the validated Anvil + localhost path instead of the broken gethDev/Hardhat-node path

Validation

Run in dedicated PC2 VM livepeer-docs-qa-20260503.

• prompt-injection scan before trusting repo content: 9,021 files inventoried; 8,641 text files scanned; 184,978,220 text bytes scanned
• mint validate: passed
• public About/Developers audit: 45 public pages, 0 missing refs, 0 duplicate refs, 0 public rooted broken links, 0 public frontmatter issues
• local Mintlify preview smoke: 45/45 current public About/Developers routes returned HTTP 200
• local protocol/go-livepeer smoke: Anvil chain, protocol deploy, round-length update, unpause, faucet request, LPT approval, bond, local go-livepeer orchestrator startup, and local go-livepeer gateway startup all passed
• no real keys, funded wallets, or mainnet actions used

Deferred follow-up

Real keyed/public-network validation is intentionally deferred. In particular, this PR does not claim validation of:

• production/public-network orchestrator registration with a funded wallet
• production gateway traffic
• paid market job flow through public gateway/orchestrator infra
• hosted API-key flows, current pricing/model-support claims, or beta-service state

Those keyed flows can be validated in a follow-up pass with the owner-provided orchestrator key.