docs: add sponsorship playbook and monthly metrics automation

SPONSORING.md

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+# Sponsoring ECC
+
+ECC is maintained as an open-source agent harness performance system across Claude Code, Cursor, OpenCode, and Codex app/CLI.
+
+## Why Sponsor
+
+Sponsorship directly funds:
+
+- Faster bug-fix and release cycles
+- Cross-platform parity work across harnesses
+- Public docs, skills, and reliability tooling that remain free for the community
+
+## Sponsorship Tiers
+
+These are practical starting points and can be adjusted for partnership scope.
+
+| Tier | Price | Best For | Includes |
+|------|-------|----------|----------|
+| Pilot Partner | $200/mo | First sponsor engagement | Monthly metrics update, roadmap preview, prioritized maintainer feedback |
+| Growth Partner | $500/mo | Teams actively adopting ECC | Pilot benefits + monthly office-hours sync + workflow integration guidance |
+| Strategic Partner | $1,000+/mo | Platform/ecosystem partnerships | Growth benefits + coordinated launch support + deeper maintainer collaboration |
+
+## Sponsor Reporting
+
+Metrics shared monthly can include:
+
+- npm downloads (`ecc-universal`, `ecc-agentshield`)
+- Repository adoption (stars, forks, contributors)
+- GitHub App install trend
+- Release cadence and reliability milestones
+
+For exact command snippets and a repeatable pull process, see [`docs/business/metrics-and-sponsorship.md`](docs/business/metrics-and-sponsorship.md).
+
+## Expectations and Scope
+
+- Sponsorship supports maintenance and acceleration; it does not transfer project ownership.
+- Feature requests are prioritized based on sponsor tier, ecosystem impact, and maintenance risk.
+- Security and reliability fixes take precedence over net-new features.
+
+## Sponsor Here
+
+- GitHub Sponsors: [https://github.com/sponsors/affaan-m](https://github.com/sponsors/affaan-m)
+- Project site: [https://ecc.tools](https://ecc.tools)