feat: harden multi-repo registry and add structural analysis #34

	name: Codegraph Impact Analysis
	on: [pull_request]
	jobs:
	impact:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v6
	with:
	fetch-depth: 0
	- uses: actions/setup-node@v6
	with:
	node-version: '22'
	- run: npm install
	- run: npx codegraph build
	- name: Run impact analysis
	run: \|
	npx codegraph diff-impact --ref origin/${{ github.base_ref }} --json > impact.json \|\| echo '{"affectedFiles":[],"summary":null}' > impact.json
	- name: Comment on PR
	uses: actions/github-script@v8
	with:
	script: \|
	const fs = require('fs');
	const impact = JSON.parse(fs.readFileSync('impact.json', 'utf-8'));
	if (!impact.summary) {
	console.log('No impact data to report.');
	return;
	}
	const body = `## Codegraph Impact Analysis\n\n` +
	`${impact.summary.functionsChanged} functions changed -> ` +
	`${impact.summary.callersAffected} callers affected across ` +
	`${impact.summary.filesAffected} files.\n\n` +
	(impact.affectedFunctions \|\| []).slice(0, 20).map(f =>
	`- \`${f.name}\` in \`${f.file}:${f.line}\` (${f.transitiveCallers} transitive callers)`
	).join('\n');
	github.rest.issues.createComment({
	owner: context.repo.owner,
	repo: context.repo.repo,
	issue_number: context.issue.number,
	body
	});

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