Add dashboard and agent subcommands so we can automate Aura's new managed tools

[ma3u]

Context

I built a hackathon entry (Apple HealthGraph Agent) and wanted my whole
pipeline reproducible from bash scripts/run.sh:

1. Create AuraDB instance → aura-cli instance create ✅
2. Snapshot / restore → aura-cli instance snapshot ✅
3. Manage tenant / data API → aura-cli tenant/dataapi ✅
4. Create dashboard from JSON → ?
5. Create agent + attach tools → ?
   Steps 4 and 5 have no CLI or public-API path today. The CLI's
   subcommands/ tree (verified at HEAD) is:
   agent config credential customermanagedkey dataapi
   deployment graphanalytics import instance tenant utils
   agent exists but only for managing one of the older agent concepts (per
   the README example), not the new in-console Aura Agents with tools
   and chat. There is no dashboard subcommand at all.
   The public REST API (api.neo4j.io/v1/*) returns 403 for every
   dashboard- or agent-related path I could think of. Only /v1/instances
   and /v1/tenants are routed.
   Meanwhile the Console UI talks to its own undocumented internal API at
   https://console.neo4j.io/api/shared-storage/v1/dashboards/dashboards
   which does support the full CRUD I'd want (POST dashboard, POST
   pages, POST widgets, PATCH, DELETE). That API only trusts user-session
   OIDC tokens from login.neo4j.com — service-account tokens from
   api.neo4j.io/oauth/token are rejected with "token-invalid" even
   though both have aud=https://console.neo4j.io.

Why this matters

Hackathon participants and anyone shipping a reproducible Aura demo need
to bootstrap the same dashboard / agent setup on every fresh tenant.
Right now we either:

• Click through the UI on every demo (not reproducible)
• Reverse-engineer the console JS bundle to call the undocumented API
  with a browser-grabbed bearer token that rotates every 15 min
  (what I ended up doing — see my upload script)
• Skip the new tools and fall back to legacy NeoDash (we did this too —
  it has the public _Neodash_Dashboard node-label storage that works
  fine from cypher-shell)

Asks

1. Dashboard CRUD via Aura API or aura-cli — accept the same JSON
   that Tools → Dashboards → Export produces, plus support the
   convert-from-NeoDash flow that the UI already implements.
2. Agent CRUD via Aura API or aura-cli — at minimum: create agent,
   attach Text2Cypher / Similarity / custom tools, set system prompt.
3. Document the schema for either route (Aura's dashboard JSON
   format is not in the public docs — I had to reverse-engineer it from
   neo4j-product-examples/sample-applications/.../*.dashboard.json
   to know that widgets replaces NeoDash's reports etc.).
   Happy to share my conversion script and the reverse-engineered request
   shapes if useful.