Build Hermes integration example with shell-free Gmail tools

[SSBrouhard]

Goal

Document and demonstrate a Hermes-facing VMGA surface that does not require shell access for normal mail operations.

Acceptance criteria

• Example tool manifest exposes structured read, draft, send, label, archive, and attachment-release flows.
• Agent-visible tools submit proposals rather than holding Gmail write credentials.
• Docs explain where Hermes stops and VMGA begins.
• Tests or fixtures exercise at least draft creation and approval-bound send.