feat: @ottabase/error-page — edge-compatible error rendering with dev/prod modes

[Copilot]

Replaces the youch naming with a generic @ottabase/error-page package. Adds production-safe error pages and integrates as the default worker error handler.

Package: @ottabase/error-page

• Edge-runtime compatible stack trace parser (V8/SpiderMonkey/JSC)
• Self-contained HTML renderer with dark/light mode, XSS escaping, CSP nonce support
• ErrorPage.toHTML() — detailed dev error page (stack trace, request metadata, error cause chain, "open in editor" links)
• ErrorPage.toProductionHTML() — minimal production page (status code + generic message, no internals)
• 53 tests across parser, renderer, and integration

Worker integration

Request	Dev	Production
HTML	Full stack trace + metadata	Clean status page
API	JSON with error message	JSON with generic message

const errorPage = new ErrorPage();

// Dev: rich error page
errorPage.addRequestMetadata(request);
const html = errorPage.toHTML(err, { title: 'Worker Error' });

// Prod: safe error page
const html = errorPage.toProductionHTML(500);

Production error page

Cleanup

Zero youch references in source code. Remaining occurrences in pnpm-lock.yaml are transitive deps from wrangler/miniflare.

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