docs: refresh engineering runbooks

[cursor]

Summary

• Updated existing engineering docs for event loading, release automation, local setup/configuration, command references, feature caveats, database notes, and test inventory.
• Covered source paths including src/handlers/events.js, src/events/Guild/interactionCreate.js, .github/workflows/release.yml, src/example.config.js, src/commands/slash/General/rank.js, src/utils/rankCardPresenceStatus.js, ticket components, JTC handler, Prisma schema, and current tests.
• Addressed stale guidance around { event, run } event registration, missing-tag release gating, explicit npx prisma generate, PRODUCTION=false MongoDB URI truthiness, required /rank info <user>, ticket/JTC setup limitations, and missing test inventory entries.

Verification

• git diff --check HEAD~1..HEAD
• stale documentation phrase scan: no matches
• npm test (37 passing tests)