chore: complete PyPI naming alignment — migrate 10 `agentmesh_*` modules to `agent-governance-toolkit-*`

[jackbatzner]

Summary

Follow-up to #1597. The naming pass closed, but 10 modules under agent-governance-python/agent-os/modules/ still publish on PyPI under the agentmesh_* prefix even though the canonical project brand is agent-governance-toolkit. The folder name says agent-os, the wheel says agentmesh, and the recommended install surface says agent-governance-toolkit — three concentric brands ship today.

Affected packages

Folder	Current PyPI name
agent-os/modules/amb	agentmesh_message_bus
agent-os/modules/atr	agentmesh_tool_registry
agent-os/modules/caas	agentmesh_context
agent-os/modules/cmvk	agentmesh_drift
agent-os/modules/control-plane	agentmesh_control_plane
agent-os/modules/emk	agentmesh_memory
agent-os/modules/iatp	agentmesh_trust_protocol
agent-os/modules/mcp-kernel-server	agentmesh_mcp_server
agent-os/modules/nexus	agentmesh_nexus
agent-os/modules/observability	agentmesh_observability

What needs to happen

For each module, decide and implement one of:

• Rename in place — new distribution agent-governance-toolkit-<module>, old name becomes a dep-only redirect stub
• Fold into umbrella — stop publishing the standalone distribution; consumers get the module via agent-governance-toolkit-core (or an extras group)
• Hybrid — keep importable module path, expose via extras (pip install agent-governance-toolkit-core[message-bus])

A consistent answer across all 10 is preferable to per-module decisions.

Constraints

• Old PyPI names need backwards-compat stubs through the deprecation window (see MIGRATION.md)
• Whatever path is chosen should match the approach used in the package consolidation follow-up (sibling issue), to avoid stubbing the same names twice
• PyPI namespace ownership for agent-governance-toolkit-* distributions should be confirmed before any rename lands

Out of scope

• Source-tree (folder) rename → separate follow-up
• Module-level convergence with parallel implementations in agent-mesh/src/agentmesh/ → tracked separately

Closes the unfinished tail of #1597.

[qubeena07]

Hey, I went through the issue and put together a fix. All 10 modules under agent-os/modules/ now use the agent-governance-toolkit-* prefix in their pyproject.toml distribution names.

I also updated the cross-module dependency references in nexus, mcp-kernel-server, iatp, and atr so they point to the new names, and updated docs/package-consolidation/AUDIT.md to match.

Since AUDIT.md confirms none of these modules are published on PyPI, no backwards-compat stubs are needed.

PR is here: #2779

Went with rename-in-place consistently for all 10 as the issue suggested rather than making per-module decisions.