docs(oss): complete adopter journey

[nstranquist]

Summary

• add conventional Quick start, Configuration, Usage, and Troubleshooting sections to the README
• add a reviewed split-plan example with safe adaptation steps
• propose Contributor Covenant 3.0 with the repository owner as moderator
• use the enabled GitHub private reporting form for confidential conduct reports
• keep the Code of Conduct requirement human-gated until owner review and merge

Stack

This pull request is based on #8 because both changes update the correction-era README and OSS evidence. Land #5, then #8, before this pull request. It does not authorize a merge, tag, or release.

Verification

• go test -count=1 ./...
• go test -race -count=1 ./...
• go vet ./...
• golangci-lint run ./...
• actionlint
• gitleaks dir . --redact --no-banner
• git fsck --strict --no-dangling
• JSON validation for the requirement ledger and example plan
• NDev skill quality: 10/10, zero errors, warnings, or informational findings
• exact NDev OSS evidence detector: all 18 adopter signals present in this checkout

Dogfood receipt

wip init used worktree mode with exact path leases. The reviewed split-plan dry-run passed before publication. The applied plan created:

1. 02cdf86 — docs(community): add conduct reporting
2. 1467b7d — docs(onboarding): complete adopter journey

The result reported gate_outcome: passed, ref_updated: true, and intent_state: complete. Plan ID: plan-3d2ffc8b25eaf2876a8e0fe9. The lane was released after an exact compare-and-swap moved this branch.

The Code of Conduct is adapted from Contributor Covenant 3.0, under its stated CC BY-SA 4.0 terms.