fix(dev): rebuild shared workspaces before npm run dev (#968)

[jakebromberg]

Summary

Adds an npm lifecycle predev script that rebuilds @wxyc/database + @wxyc/authentication before npm run dev, so a fresh clone or any pull that touches shared/database/src/schema.ts doesn't silently serve a stale schema export to the running backend.

The failure mode this prevents is brutal to diagnose: every flowsheet read 500s with TypeError: Cannot convert undefined or null to object deep inside drizzle-orm/utils.js (orderSelectedFields), with no column name in the stack to chase. Took ~20 minutes to trace during the BS#940 / dj-site#560 preview session on 2026-05-18 before noticing the dist/index.js mtime predated the schema commit.

apps/backend/tsup --watch rebuilds its own sources but doesn't follow workspace dep dists; predev covers the gap.

Change

+ "predev": "npm run build --workspace=@wxyc/database --workspace=@wxyc/authentication",

Mirrors the existing lint:prebuild shape — same workspaces, same npm run build invocation. CLAUDE.md "Running locally" gets a one-paragraph note explaining the why.

Test plan

• Wiped shared/database/dist + shared/authentication/dist; ran npm run predev. Both rebuilt successfully (DTS clean, ~1s wall clock). Verified flowsheet.track_position (the symbol whose absence trips the original bug) is present in the regenerated dist/index.js.
• npm run dev now chains predev first per npm lifecycle convention. Already runs dotenvx run -f .env -- concurrently for the actual dev startup; predev runs in a separate shell invocation so dotenvx wrapping is irrelevant.
• No CI changes — lint:prebuild already covers the shared-workspace rebuild for lint/typecheck/build CI jobs, so CI is untouched.

Notes

• Why not --workspaces --if-present? Would also build apps/* and jobs/*, which tsup --watch in dev:backend / dev:auth already handles. ~1s vs ~5s startup delta isn't a lot, but the explicit-list approach matches lint:prebuild and is self-documenting.
• Why not switch the exports map to point at ./src/index.ts? Bigger change with implications for production build paths; the predev path is the smaller fix and matches the in-flight convention. If anyone wants to revisit the exports-condition approach, that's a separate ticket.

Related

• Closes npm run dev silently serves stale @wxyc/database when shared/database/dist is out of date #968
• Surfaced during the Add /library/rotation/:rotation_id/tracks — tracks dropdown for rotation entry mode #940 / fix(rotation): auto-fill artist from track per-track credits (#518) dj-site#560 preview session 2026-05-18.