face-lift: README restructure, conventions, ledger, check-knowledge harness, lint CI

[lookathim010-source]

What changed

README restructured around who writes what (connector vs sessions vs humans), with a layout table, the lesson shape, how to read and how to check the repo. Added CONTRIBUTING.md (connector-owned vs hand-owned files, PR and ledger rules), LEDGER.md (hand/session changes only), .gitignore, .markdownlint.yml (lenient so connector output passes unchanged), a PR template, harness/check-knowledge.py (PASS/FAIL structural check: H1, newest-first day sections, every lesson has why/do/source+confidence, lessons/ coverage and counts, verified/ naming), and .github/workflows/lint.yml (markdownlint + the harness).

Connector-managed files: knowledge.md and lessons/ are untouched. verified/2026-09-26_claude-surfaces_v1.md got whitespace-only lint fixes and one bare URL wrapped in angle brackets; content unchanged.

How it was verified

markdownlint-cli2 v0.23.3 — Linting: 7 files — Summary: 0 issues in 0 files
python3 harness/check-knowledge.py
  RESULT: PASS — 9 pass, 0 warn, 0 fail
negative test (renamed one "Do:" line, then restored):
  FAIL knowledge:lesson-shape   1 missing field(s): 2026-08-24#1:do
  RESULT: FAIL — 8 pass, 0 warn, 1 fail
yaml: .github/workflows/lint.yml and .markdownlint.yml parse

Where the risk lives

• The harness enforces the lesson shape the connector currently emits. If the connector's output format changes, CI on the next connector commit to main goes red — which is the point, but it will page as a failure. Loosen SOURCE_RE in the harness if the change is intentional.
• Live Actions badge in the README shows "no status" until this workflow has run once on main.

Ledger

• Row added to LEDGER.md

🤖 Generated with Claude Code

https://claude.ai/code/session_01T7N2VsxDrRZPwWM7zdFnuK

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Generated by Claude Code

Summary by Sourcery

Establish repository conventions and automated checks for maintaining connector-generated lessons alongside session-verified knowledge.

New Features:

• Add a structural knowledge validation harness covering lesson format, daily-file coverage, verified-file naming, and content consistency.
• Add repository conventions, change ledger, pull request template, and a restructured README explaining repository ownership, layout, lesson format, and validation.

Bug Fixes:

• Apply formatting-only Markdown lint fixes to the verified Claude surfaces fact sheet without changing its content.

Enhancements:

• Define connector-owned versus human-owned files and establish branch, pull request, ledger, and linting conventions.

CI:

• Add GitHub Actions checks for Markdown linting and the knowledge validation harness on pushes and pull requests.

Documentation:

• Restructure the README around repository layout, lesson shape, reading guidance, and validation instructions.

Tests:

• Add positive and negative validation coverage for the knowledge repository contract, including JSON output support.

Chores:

• Add repository ignore rules and Markdown lint configuration tuned for connector-generated content.