feat: PostHog sourcemaps + server logs (OpenTelemetry)

[mbifulco]

Summary

Adds production-error observability for the site via PostHog:

1. Sourcemap upload — next.config.mjs now wraps the build with @posthog/nextjs-config's withPostHogConfig (outermost wrapper), gated to VERCEL_ENV === 'production' with deleteAfterUpload: true. Production JS errors will show unminified stack traces in PostHog Error Tracking. Because injection must run on the deployed build, this hooks into the Vercel build rather than a GitHub Action.
2. Server logs via OpenTelemetry — src/instrumentation.ts stands up an OTLP log pipeline (src/server/logging/otel-logs.ts) that patches console.* to also emit OTel log records to PostHog Logs (/i/v1/logs, authed with the public project token). flushLogs() is wired into the tRPC handler (try/finally) and the llms.txt route (after()) so batches flush before serverless freeze.
3. Host consolidation — all PostHog host strings moved into src/lib/posthog/hosts.ts; the client provider, server client, logs endpoint, and next.config rewrites + wrapper host all import from it. Resolved URLs are byte-identical (prod client still uses the /ingest reverse proxy).
4. PII hygiene — since the console bridge ships all server logs to PostHog Logs, trimmed the Resend webhook logs to non-PII identifiers (no subscriber email/name).

Commits

• 7eb2ed1 sourcemap upload via @posthog/nextjs-config
• fab4957 OTel server-log pipeline + console bridge
• 2b09179 flush wiring (tRPC + llms.txt)
• 5293a16 eslint fix (type-only import)
• c676a35 centralize PostHog host config
• c371864 trim subscriber PII from webhook logs

Manual setup required before this works in prod

• Add POSTHOG_PERSONAL_API_KEY to Vercel (Production scope) — a personal API key with write access to Error Tracking.
• Confirm NEXT_PUBLIC_POSTHOG_HOST is unset or points at a real PostHog host (us.i.posthog.com), not the mikebifulco.com/ingest reverse proxy — the sourcemap upload API is not proxied.
• After deploy: verify a symbol set appears in PostHog → Error Tracking, and a line appears in PostHog → Logs.

Reviewer notes (non-blocking)

• Log volume/cost: every server console.* line now ships to PostHog Logs. Consider severity/source filtering or sampling if quota becomes a concern.
• Error stacks: stringifyArg renders Error as name: message (no stack) in log bodies — stacks are expected to come from Error Tracking + sourcemaps.

Verification

pnpm typecheck, pnpm lint, and pnpm build pass (aside from one pre-existing src/lib/unified-feed.test.ts type error unrelated to this branch). Unit tests: 218 passing. New unit coverage for the OTel logging module and the host constants.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
mikebifulco-com-bnbu	Ready	Preview, Comment	Jul 8, 2026 11:36am

[Copilot]

Pull request overview

Adds PostHog-based production observability by uploading Next.js sourcemaps at build time and exporting server-side console logs via an OpenTelemetry OTLP log pipeline, while centralizing PostHog host configuration and reducing PII in webhook logging.

Changes:

• Integrates @posthog/nextjs-config into next.config.mjs to upload sourcemaps in production.
• Adds an OTLP log exporter + console bridge and wires flushLogs() into request/route teardown paths.
• Centralizes PostHog host constants and updates client/server PostHog configuration to reference them; trims webhook log PII.

Reviewed changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/server/posthog.ts	Switches server PostHog client default host to centralized constant.
src/server/logging/otel-logs.ts	Adds OTLP logging pipeline and console bridge to emit server logs to PostHog.
src/server/logging/otel-logs.test.ts	Adds unit tests for severity mapping, console bridge behavior, and flush safety.
src/pages/api/trpc/[trpc].ts	Flushes pending logs after each tRPC API request via finally.
src/pages/api/inbound_webhooks/resend.ts	Reduces PII in webhook logs now that server logs are exported.
src/lib/posthog/hosts.ts	Introduces centralized PostHog host constants (API/assets/UI/proxy/logs endpoint).
src/lib/posthog/hosts.test.ts	Adds unit tests to enforce host constant values/derivations.
src/instrumentation.ts	Registers server logging via Next.js instrumentation hook.
src/app/posthog-provider.tsx	Updates client PostHog init to use centralized host constants.
src/app/llms.txt/route.ts	Schedules log flush after request completion using after().
pnpm-workspace.yaml	Allows @posthog/cli to run build steps under pnpm policy.
pnpm-lock.yaml	Locks new PostHog config + OpenTelemetry logging dependencies.
package.json	Adds @posthog/nextjs-config and OpenTelemetry logging packages.
next.config.mjs	Adds PostHog sourcemap upload wrapper + rewrites updated to use centralized hosts.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

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