[WIP] feat/labs migration

[alanpeixinho]

Summary

Migrates all read paths for lab information from JSONB misc fields (builds.misc->>'lab',
tests.misc->>'runtime') to the new labs table via lab_id foreign key, with JSONB fallback for rows not yet backfilled.
Every SQL query and Python helper that previously extracted lab names by parsing JSONB now uses COALESCE(labs.name, misc_fallback) through a LEFT JOIN on the labs table. This ensures:

• New data (with lab_id populated by the ingester) reads from the structured FK
• Historical data (without lab_id) still works via the JSONB fallback
• After a full backfill, the JSONB fallbacks can be removed (all marked with TODO comments)

How to test

legacy database

• Use a database where lab_id is NULL on existing rows
• Verify all pages display lab names as before:
  • Tree details page (boots/tests tabs) — lab column in test history
  • Tree commits history page — build lab and test lab in filters and rows
  • Hardware details page — lab in test/build summaries, history, and filters
  • Build details page — lab column in test list
  • Issue details page — lab column in test list
  • Notifications/metrics endpoint — lab summary counts

Migrated database (test in a local database)

• Run the migrations available
• Run the ingester (which already fills lab_id)
  • Verify all pages display lab names as before:
  • Tree details page (boots/tests tabs) — lab column in test history
  • Tree commits history page — build lab and test lab in filters and rows
  • Hardware details page — lab in test/build summaries, history, and filters
  • Build details page — lab column in test list
  • Issue details page — lab column in test list
  • Notifications/metrics endpoint — lab summary counts