feat: expose Prophet workspace hook RPC methods

[mdheller]

Summary

This PR wires the existing Prophet workspace no-op hooks into callable Gateway RPC methods.

It updates extensions/prophet-workspace/index.ts to expose:

• prophetWorkspace.emitCarrier
• prophetWorkspace.evaluateMembraneDecision
• prophetWorkspace.appendLedgerEvent
• prophetWorkspace.resolveConnectedAppGrant

Why

The merged skeleton added the Prophet workspace plugin and hook contracts. This PR makes those hook points callable through OpenClaw's existing Gateway RPC extension model, still without mutating Prophet state.

What this does

• imports createNoopProphetWorkspaceHooks
• instantiates no-op hook implementations in the plugin register path
• exposes dry-run Gateway RPC methods for each hook class
• updates the status payload to report the hook RPC phase

What this does not do yet

• call a real Prophet service
• emit a real PPS carrier
• append a real ledger event
• resolve a real connected-app grant
• mutate workspace state

Upstream alignment

This follows OpenClaw's existing plugin model instead of adding a parallel runtime boundary.

Follow-up

1. Replace one no-op hook with a local Prophet endpoint call.
2. Add a smoke test fixture or CLI call for prophetWorkspace.status and one hook RPC.
3. Route one narrow action through the hook path and render the returned receipt.