docs(gitbuilt): add GitHub opportunity map

[HitsuyoAkuWeb3]

Business Change

Adds a public-safe strategy artifact that positions GitBuilt as an evidence-based builder activation and agentic proof lab for a future GitHub sponsorship conversation.

Why Now

The existing course and partnership recon need a durable, inspectable record of the opportunities beyond the original sponsorship lanes, including current product paths and explicit lifecycle guardrails.

What Changed

• added the GitBuilt × GitHub Opportunity Map
• defined a two-tier Foundations-to-Proof and Agentic Proof Lab pilot
• framed future sponsorship inventory as unconfirmed and eligibility-dependent
• added evidence, measurement, lifecycle, ownership, and non-affiliation boundaries
• linked the map from the repository and proof-package entry points
• updated the changelog

Promotion Check

• Source layer named: owner-directed internal recon promoted to GitHub public-review branch
• Owner named: Red Pillar and Hitsuyo Aku, under KnowTheLedge
• Approval path clear: both owners approve before merge or official external use
• Sensitive data removed
• Evidence attached through official GitHub sources and local validation

Proof

• Four intended public-repo files updated
• git diff --check passed
• All 15 external evidence links returned HTTP 200
• Public-boundary scan found no local paths or internal C-suite deliberation
• No GitHub settings change is required

Risk

This affects public positioning. The document avoids promises of affiliation, sponsorship benefits, partner acceptance, certification, hiring, or Marketplace placement. Product and program availability must be rechecked before outreach.

Decision Needed

Approve, revise, block, or defer the opportunity map and proposed pilot framing.

After Merge

Select the first Foundations-to-Proof lesson, confirm participant eligibility and existing benefits, choose the advanced proof artifact, and define human-review, security, and measurement gates before approaching GitHub.