Re-taking the README screenshots

The images in docs/assets/dashboard-*.png are produced from a throwaway instance seeded with synthetic telemetry, never from a real one. Real telemetry carries real user names and real spend, and a screenshot is forever.

Redo them whenever a page in the shot changes shape.

1. Build the image under test

docker build -t cotel:shots .

2. Run it on a fresh volume, with retention off

The seed reaches 90 days back; the shipped 30-day raw retention would roll most of it into daily_usage mid-run and the session rows would vanish from the list.

docker run -d --name cotel-shots \
  -p 14318:4318 -p 18080:8080 \
  -e COTEL_RETENTION_RAW_DAYS=3650 \
  -e COTEL_RETENTION_AGGREGATE_DAYS=3650 \
  -v cotel-shots-data:/data \
  cotel:shots

3. Seed it

python3 scripts/seed-demo.py --dash-url http://localhost:18080 \
                             --ingest-url http://localhost:14318

Takes a couple of minutes and ingests ~25 000 spans across ~485 sessions. The RNG seed is fixed, so a re-run against a fresh volume reproduces the same numbers. Ingest is queued behind the HTTP response — wait for span_count in curl -s localhost:18080/api/v1/health to stop climbing before shooting.

4. Shoot

BASE=http://localhost:18080 node scripts/shoot-screenshots.mjs

1440×1400 viewport at 2× DPR, dark scheme, each page cropped at the bottom edge of a named element. The files land straight in docs/assets/.

playwright-core has to be resolvable from the script — npx playwright-core@latest --help once is enough to populate the npx cache, then symlink it into a node_modules/ beside the script. It has to be a symlink: the script is an ES module and ESM resolution ignores NODE_PATH. Chromium comes from CHROMIUM (default /usr/bin/chromium); this box has no Playwright-managed browser.

5. Tear down

docker rm -f cotel-shots && docker volume rm cotel-shots-data

What not to fake

The seeder sends only the attributes Claude Code actually sends. In particular it does not attach command to Bash spans, so the Tools page's Bash breakdown shows its "no command detail in this data" state — which is what a real install sees. Seeding it would make the README advertise a view nobody gets.