chore: initial scaffolding for SynthesisAgent

Bridge between OpenClaw (multi-channel hub) and interactive Claude Code,
keeping autonomous agent usage on the subscription quota after the
2026-06-15 Agent SDK credit split.

Initial scaffolding only — two submodules with skeletons:

- SynthesisAgent.ClaudePlugin: stdio MCP server registered as a --channels
  source. Declares experimental.claude/channel capability (verified 2026-05-14
  against the official Anthropic discord plugin) and emits
  notifications/claude/channel to push OpenClaw inbound messages into the
  Claude turn loop.

- SynthesisAgent.OpenclawPlugin: process manager + session mapping +
  bridge WebSocket. Currently shaped around a custom ws protocol; will be
  rewritten as a model-provider HTTP server (contractor-agent pattern) so
  OpenClaw routes inbound channel messages through it via /v1/chat/completions.

See STATUS.md for the open punch list and docs/wire-protocol.md for the
(soon-to-change) inter-plugin frame schema.

SynthesisAgent.ClaudePlugin/.claude-plugin/plugin.json

@@ -0,0 +1,6 @@
+{
+  "name": "synthesis-claude",
+  "description": "Claude Code channel plugin for SynthesisAgent — bridges OpenClaw events into Claude Code via notifications/claude/channel, and proxies OpenClaw tool calls back to OpenClaw.",
+  "version": "0.0.1",
+  "keywords": ["openclaw", "channel", "mcp", "synthesis"]
+}