feat(comms): org-management agent tools — comms adapters, hub dispatch, spawn role/persona (RIG-2673)

[rigel-mintaka]

This PR is part of a stack containing 2 PRs:

1. main
2. feat(proto): org-management comms + spawn arms for agent gateway (RIG-2673) #628
3. "feat(comms): org-management agent tools — comms adapters, hub dispatch, spawn role/persona (RIG-2673)" (this PR)

Wires the compass-server half of the org-management agent tools (RIG-2673 T2–T4) on top of the T1 proto arms (#628): the three comms adapters, their hub dispatch, and the spawn role/persona thread-through. Every operation flows through the existing agent→Runner→Server relay under the server-resolved account, so the authz, idempotency, and event fan-out are identical to a human caller's.

T2 — comms adapters (go/internal/comms/agent_caller.go)

CreateChannelAsAccount, UpdateChannelMembersAsAccount, CreateChannelGroupAsAccount — each mirrors UpdatePinnedBoardAsAccount: guard empty account → errNoActor, then WithActor + the shared handler path, returning resp.Msg. No home-channel defaulting (create-channel names no channel; update-members carries channel_id explicitly; create-group names only an optional parent). Founding membership rides CreateChannel's expandOwnerMembership, so a Manager can immediately post to the channel it just made.

T3 — hub dispatch (go/internal/runnerhub/hub.go, relay_comms.go)

Extended the CommsCaller interface with the three methods and added three executeCall cases on the Pin pattern, each wrapping the matching CommsCallResult oneof. The default-case error string's variant list now includes the three new arms. A tool error renders in-band as CommsCallError, never a stream teardown.

T4 — spawn role/persona thread-through (go/server/lifecycle.go)

Dropped the Persona: "" / Role: "" hardcodes in the store.CreateAgent literal for req.GetPersona() / req.GetRole(). Under the D9 owner-acts model the caller's owner is the authority, so a Manager-creating spawn legitimately carries role+persona set-at-creation; the values are stored via CreateAgent (the source of record) and threaded to the Runner from the created store account — an empty-field spawn is byte-identical to today's field-less spawn.

Tests (red-green)

• T2 pgtests (org_mgmt_pgtest_test.go): founder-membership + ChannelChanged fan-out, member-add, group-create; each with empty-account → errNoActor and an invisible/non-member target → CodeNotFound (the D9 collapse a human gets).
• T3 relay tests (relay_org_mgmt_test.go): each arm forwards under the bound account with call_id round-trip; a create-channel tool error is in-band, not a transport teardown.
• T4 spawn pgtests (spawn_role_persona_pgtest_test.go): role and persona each stored + on the Provision wire; empty-field spawn stores + wires empty (wire-level regression); idempotent re-spawn keeps stored values.

Verified: go build ./..., gofmt, compass-go:lint (0 issues), and the affected internal/comms / internal/runnerhub / server suites all green (pgtests via the throwaway-container path).

Refs RIG-2724, RIG-2673.

Co-authored-by: Matt Wilkinson matt@rigel.build

[linear-code]

RIG-2724

RIG-2673

[github-actions]

Compass engineering docs preview: https://compass-server-rig-2724-org-au33.compass-eng-docs.pages.dev

Deployed from compass-server/rig-2724-org-mgmt-handlers at 10fb626.