grammarly-upgrade-migration

# Grammarly Upgrade & Migration ## Overview Grammarly exposes versioned APIs for writing analysis, AI detection, and plagiarism checking. Each API family versions independently — the Writing Score API may be on v2 while AI Detection remains on v1. Tracking these versions matters because Grammarly deprecates older API versions on a fixed timeline, and the response schemas differ significantly between versions (score breakdowns, suggestion categories, and confidence thresholds all change). Missing a version cutover means silent failures or degraded writing feedback quality. ## Version Detection ```typescript const GRAMMARLY_BASE = "https://api.grammarly.com/ecosystem/api"; interface GrammarlyVersionMap { scores: string; aiDetection: string; plagiarism: string; latestAvailable: Record<string, string>; } async function detectGrammarlyVersions(apiKey: string): Promise<GrammarlyVersionMap> { const endpoints = { scores: `${GRAMMARLY_BASE}/v2/scores`, aiDetection: `${GRAMMARLY_BASE}/v1/ai-detection`, plagiarism: `${GRAMMARLY_BASE}/v1/plagiarism`, }; const versions: Record<string, string> = {}; for (const [api, url] of Object.entries(endpoints)) { const res = await fetch(url, { method: "HEAD", headers: { Authorization: `Bearer ${apiKey}` }, }); versions[api] = res.headers.get("x-grammarly-api-version") ?? "unknown"; const deprecated = res.headers.get("x-grammarly-deprecated"); if (deprecated) console.warn(`${api} endpo...