feat: seed script, forgot-password, hover cards, shortcuts, OpenAPI docs, runbook (phase 12)

- scripts/seed.go: idempotent demo data per §11.11 (make seed)
- forgot/reset password: SMTP-gated, one-shot TTL tokens, uniform responses
  against enumeration, sessions revoked on reset; login page link + pages
- profile hover cards on [data-user-card] elements (§11.13)
- keyboard shortcuts: g b/m/t/h navigation, / focuses search (§10)
- bulk archive endpoint (§11.9)
- hand-written OpenAPI 3.1 covering §6, served at /api/docs + yaml download
- make backup / make restore (mongodump archive via the mongo container)
- README: quick start, demo data, runbook, breaker/job operations, working
  Caddy + nginx reverse-proxy samples (WS block, client_max_body_size),
  documented later-stubs (§11.24)
- smoke.sh now exercises register → logout → login → me → board → pages

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

api/api.go

@@ -0,0 +1,7 @@
+// Package api embeds the hand-written OpenAPI document (§6).
+package api
+
+import _ "embed"
+
+//go:embed openapi.yaml
+var OpenAPI []byte