fix(zulip): replace subprocess spawn with direct session injection

- Removed spawnSync subprocess (pi -p --mode json) for Zulip DM processing
- Messages now inject directly into the current pi session via
  pi.sendUserMessage(), reusing the already-hot LLM — zero cold-start
- agent_end event handler captures assistant response and relays it to Zulip
- Added pending reply queue for ordered delivery of multiple Zulip messages
- Fixed zulip-js import (CJS default export, not named createClient)
- Added types.d.ts for zulip-js with default export declaration
- Updated package.json with yaml dependency, @earendil-works/pi-coding-agent
- Config supports both nested YAML and flat env-var formats
- Removed all subprocess timeout/buffer error paths (no longer needed)

pi-zulip-extension/package.json

@@ -9,14 +9,20 @@
     "check": "tsc --noEmit"
   },
   "dependencies": {
-    "zulip-js": "^2.0.0",
-    "yaml": "^2.0.0"
+    "yaml": "^2.9.0",
+    "zulip-js": "^2.0.0"
   },
   "devDependencies": {
-    "@earendil-works/pi-coding-agent": "*",
+    "@earendil-works/pi-coding-agent": "^0.80.2",
     "typescript": "^5.0.0"
   },
-  "keywords": ["pi", "zulip", "agent", "abiba", "sysloggh"],
+  "keywords": [
+    "pi",
+    "zulip",
+    "agent",
+    "abiba",
+    "sysloggh"
+  ],
   "license": "UNLICENSED",
   "private": true
 }