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.OpenclawPlugin/core/config.ts

@@ -0,0 +1,42 @@
+import { homedir } from 'node:os'
+import { resolve as resolvePath } from 'node:path'
+
+export interface SynthesisConfig {
+  bridgePort: number
+  bridgeToken: string
+  claudePluginRef: string
+  permissionMode: string
+  idleKillMs: number
+  maxProcesses: number
+  mappingDbPath: string
+}
+
+const DEFAULTS: SynthesisConfig = {
+  bridgePort: 18801,
+  bridgeToken: 'synthesis-local',
+  claudePluginRef: 'plugin:synthesis-claude@local',
+  permissionMode: 'acceptEdits',
+  idleKillMs: 3_600_000,
+  maxProcesses: 16,
+  mappingDbPath: '~/.openclaw/synthesis/sessions.json',
+}
+
+function expand(p: string): string {
+  if (p.startsWith('~')) return resolvePath(homedir(), p.slice(2))
+  return resolvePath(p)
+}
+
+export function normalizeConfig(raw: unknown): SynthesisConfig {
+  const r = (raw ?? {}) as Partial<SynthesisConfig>
+  const merged: SynthesisConfig = {
+    bridgePort: typeof r.bridgePort === 'number' ? r.bridgePort : DEFAULTS.bridgePort,
+    bridgeToken: typeof r.bridgeToken === 'string' && r.bridgeToken ? r.bridgeToken : DEFAULTS.bridgeToken,
+    claudePluginRef: typeof r.claudePluginRef === 'string' && r.claudePluginRef ? r.claudePluginRef : DEFAULTS.claudePluginRef,
+    permissionMode: typeof r.permissionMode === 'string' && r.permissionMode ? r.permissionMode : DEFAULTS.permissionMode,
+    idleKillMs: typeof r.idleKillMs === 'number' ? r.idleKillMs : DEFAULTS.idleKillMs,
+    maxProcesses: typeof r.maxProcesses === 'number' ? r.maxProcesses : DEFAULTS.maxProcesses,
+    mappingDbPath: typeof r.mappingDbPath === 'string' && r.mappingDbPath ? r.mappingDbPath : DEFAULTS.mappingDbPath,
+  }
+  merged.mappingDbPath = expand(merged.mappingDbPath)
+  return merged
+}