feat: openclaw-style secrets (env.vars + \) and per-task model routing

- Replace python-dotenv with config.json env.vars block + \ substitution
- Add models section for per-task model routing (heartbeat, subagent, default)
- Heartbeat/subagent tasks can use different models/providers than main chat
- Remove python-dotenv from dependencies
- Update all docs to reflect new config approach
- Reorganize docs into project/ and research/ subdirectories

cli.py

@@ -82,10 +82,6 @@ def chat(message):
     """One-shot chat with the AI."""
     import logging
 
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
     cfg = load_config()
 
@@ -125,10 +121,6 @@ def chat(message):
 @cli.command()
 def status():
     """Show runtime status."""
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
     cfg = load_config()
 
@@ -167,10 +159,6 @@ def cron():
 @cron.command("list")
 def cron_list():
     """List scheduled jobs."""
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
 
     try:
@@ -195,10 +183,6 @@ def cron_list():
 @click.argument("job_id")
 def cron_remove(job_id):
     """Remove a scheduled job."""
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
 
     try:
@@ -278,10 +262,6 @@ def memory_search(query):
     import asyncio
     import logging
 
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
     cfg = load_config()
 
@@ -315,10 +295,6 @@ def memory_sync():
     import asyncio
     import logging
 
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     save_default_config()
     cfg = load_config()
 
@@ -353,10 +329,6 @@ def doctor():
     """Run diagnostics."""
     import shutil
 
-    from dotenv import load_dotenv
-
-    load_dotenv()
-
     click.echo("🩺 Aetheel Doctor")
     click.echo()
 
@@ -373,7 +345,7 @@ def doctor():
         click.echo(f"  ⚠️  No config file at {CONFIG_PATH}")
 
     # Check workspace
-    cfg = load_config()
+    cfg = load_config()  # also applies env.vars to process env
     workspace = os.path.expanduser(cfg.memory.workspace)
     if os.path.isdir(workspace):
         click.echo(f"  ✅ Workspace: {workspace}")