feat: HTTP /v1/chat/completions + WS bridge + process manager

Real first cut. OpenClaw routes agent turns via /v1/chat/completions
(OpenAI-compatible SSE) into our bridge. Bridge ensures a long-lived
claude process per session-key, pushes the user message as
notifications/claude/channel into the running Claude Code, awaits a
reply via the WS connection, streams the reply back as SSE deltas.

- core/process-manager: spawn / track / reap claude processes, auto-confirm
  the --dangerously-load-development-channels dev-mode prompt by piping
  "1\n" to stdin shortly after spawn
- web/bridge-server: unified HTTP + WS server, per-session FIFO queue,
  SSE heartbeat (empty content delta — SSE comments don't reset OpenClaw's
  idle watchdog), reply buffering for streaming progress chunks
- index.ts: definePluginEntry for OpenClaw runtime + standalone-mode main
  for laptop smoke testing (just `bun index.ts`)

Same-machine simplifications: no bridge token, no permission_request
reverse channel. Session key = agent_id::chat_id (contractor-agent
convention).

openclaw.plugin.json

@@ -1,7 +1,7 @@
 {
   "id": "synthesis-agent",
   "name": "SynthesisAgent",
-  "description": "Manages long-lived interactive Claude Code processes per OpenClaw session; bridges OpenClaw events <-> SynthesisAgent.ClaudePlugin",
+  "description": "Routes OpenClaw agent turns through long-lived interactive Claude Code processes; replaces the claude -p path so usage stays on the subscription quota",
   "activation": {
     "onStartup": true
   },
@@ -14,22 +14,17 @@
     "properties": {
       "bridgePort": {
         "type": "number",
-        "default": 18801,
-        "description": "TCP port the bridge WebSocket server binds on (127.0.0.1)"
+        "default": 18900,
+        "description": "HTTP port for the OpenAI-compatible /v1/chat/completions endpoint that OpenClaw routes agent turns to"
       },
-      "bridgeToken": {
-        "type": "string",
-        "default": "synthesis-local",
-        "description": "Shared secret each ClaudePlugin instance must present in its hello frame"
-      },
-      "claudePluginRef": {
-        "type": "string",
-        "default": "plugin:synthesis-claude@local",
-        "description": "The --channels argument passed to claude on spawn"
+      "channelWsPort": {
+        "type": "number",
+        "default": 18901,
+        "description": "WebSocket port that each spawned Claude process's ClaudePlugin dials back into"
       },
       "permissionMode": {
         "type": "string",
-        "default": "acceptEdits",
+        "default": "bypassPermissions",
         "description": "Claude Code permission mode for spawned sessions"
       },
       "idleKillMs": {
@@ -45,7 +40,12 @@
       "mappingDbPath": {
         "type": "string",
         "default": "~/.openclaw/synthesis/sessions.json",
-        "description": "Where openclaw_session <-> claude_session UUID mapping is persisted"
+        "description": "Where openclaw_session ↔ claude_session_uuid mapping is persisted"
+      },
+      "channelName": {
+        "type": "string",
+        "default": "synthesis",
+        "description": "Name used in `--channels server:<name>` when spawning claude; must match the MCP server name in ClaudePlugin's .mcp.json"
       }
     }
   }