feat: engine/model in audit log + docs update

- tool_audit: ContextVars (engine, model) set at orchestrator run start; fields added to every entry
- orchestrator_engine: tool_audit.set_context("gemini", model_name) at run() start
- openai_orchestrator: tool_audit.set_context("openai", model label) at run() start
- audit table: Model column between Status and Args
- HELP.md: push notifications section, audit log in Files section, tool count 30→40, new API endpoints
- TODO__Agents.md: web_push and audit log marked complete with full detail

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/tool_audit.py

@@ -16,6 +16,7 @@ Each line is a JSON object:
 import asyncio
 import json
 import logging
+from contextvars import ContextVar
 from datetime import datetime, date
 from pathlib import Path
 
@@ -29,6 +30,16 @@ _SNIPPET_MAX = 300   # chars of result to keep as snippet
 # Per-file write locks — prevents interleaved lines under concurrent tool calls
 _locks: dict[str, asyncio.Lock] = {}
 
+# ContextVars set by orchestrators before their tool loop runs
+_audit_engine: ContextVar[str] = ContextVar("_audit_engine", default="")
+_audit_model:  ContextVar[str] = ContextVar("_audit_model",  default="")
+
+
+def set_context(engine: str, model: str) -> None:
+    """Call at the start of each orchestrator run to tag subsequent tool calls."""
+    _audit_engine.set(engine)
+    _audit_model.set(model)
+
 
 def _truncate_args(args: dict) -> dict:
     out = {}
@@ -63,6 +74,8 @@ async def record(
     entry = {
         "ts":             datetime.now().isoformat(timespec="seconds"),
         "user":           user,
+        "engine":         _audit_engine.get(),
+        "model":          _audit_model.get(),
         "tool":           tool,
         "args":           _truncate_args(args),
         "status":         status,