feat: multi-user/multi-persona support with two-level home directory layout

Restructures persona storage from a flat personas/{name}/ layout to
home/{username}/persona/{name}/, mirroring Linux home directories.

Changes:
- persona.py: two ContextVars (user + persona), Linux-style name validation,
  set_context(), get_user(), get_persona(), validate(), list_users(),
  list_user_personas(); persona_path() takes (username, name)
- config.py: replaces personas_dir with home_dir + home_root()
- git mv personas/inara → home/scott/persona/inara (history preserved)
- home/holly/persona/tina/: Holly's persona stub added
- cron_runner.py: all storage functions take (username, persona) params
- tools/cron.py: stamps user + persona on jobs; APScheduler IDs are
  {user}:{persona}:{job_id} to prevent collisions across users
- memory_distiller.py: distill_short/mid/long take (username, persona);
  added missing Path + settings imports
- scheduler.py: _load_user_crons() iterates home/*/persona/* (two-level)
- routers/chat.py, orchestrator.py: user field added; set_context() called
- tests/conftest.py: home_root fixture with two-level structure;
  patches home_dir instead of personas_dir
- tests/test_persona.py: fully rewritten for two-level API
- tests/test_api_files.py: updated fixture name and path
- .env.default: documents HOME_DIR setting; scrubs stale API key
- CLAUDE.md, README.md: directory maps updated for new layout

All 80 tests pass.

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

cortex/tests/test_persona.py

@@ -1,5 +1,6 @@
 """
 Unit tests for persona.py — validation, routing, path traversal.
+Tests the two-level home/{username}/persona/{name}/ structure.
 No HTTP involved.
 """
 import pytest
@@ -7,88 +8,118 @@ from pathlib import Path
 from unittest.mock import patch
 
 
-def _make_temp_personas(tmp_path: Path) -> Path:
-    root = tmp_path / "personas"
-    for name in ("alice", "bob"):
-        p = root / name
+def _make_home(tmp_path: Path) -> Path:
+    """Create a minimal home/ tree with two users and some personas."""
+    root = tmp_path / "home"
+    for username, persona in [("scott", "inara"), ("holly", "tina"), ("scott", "alt")]:
+        p = root / username / "persona" / persona
         p.mkdir(parents=True)
-        (p / "IDENTITY.md").write_text(f"# {name}")
-    # A directory WITHOUT IDENTITY.md — should not appear in list_personas()
-    (root / "incomplete").mkdir()
+        (p / "IDENTITY.md").write_text(f"# {persona}")
+    # A persona dir WITHOUT IDENTITY.md — should be invisible to list_user_personas()
+    incomplete = root / "scott" / "persona" / "broken"
+    incomplete.mkdir(parents=True)
     return root
 
 
 def test_validate_good(tmp_path):
-    root = _make_temp_personas(tmp_path)
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        assert persona.validate("alice") == "alice"
-        assert persona.validate("bob") == "bob"
+    with patch.object(config.settings, "home_dir", root):
+        assert persona.validate("scott", "inara") == ("scott", "inara")
+        assert persona.validate("holly", "tina") == ("holly", "tina")
 
 
-def test_validate_unknown(tmp_path):
-    root = _make_temp_personas(tmp_path)
+def test_validate_unknown_user(tmp_path):
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
+    with patch.object(config.settings, "home_dir", root):
+        with pytest.raises(ValueError, match="Unknown user"):
+            persona.validate("charlie", "inara")
+
+
+def test_validate_unknown_persona(tmp_path):
+    root = _make_home(tmp_path)
+    import config, persona
+    with patch.object(config.settings, "home_dir", root):
         with pytest.raises(ValueError, match="Unknown persona"):
-            persona.validate("charlie")
+            persona.validate("scott", "ghost")
 
 
 def test_validate_path_traversal(tmp_path):
-    root = _make_temp_personas(tmp_path)
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        with pytest.raises(ValueError, match="Invalid persona name"):
-            persona.validate("../../etc/passwd")
-        with pytest.raises(ValueError, match="Invalid persona name"):
-            persona.validate("../alice")
-        with pytest.raises(ValueError, match="Invalid persona name"):
-            persona.validate("alice/../../etc")
+    with patch.object(config.settings, "home_dir", root):
+        for bad in ("../../etc/passwd", "../scott", "scott/../../etc"):
+            with pytest.raises(ValueError, match="Invalid"):
+                persona.validate(bad, "inara")
+        with pytest.raises(ValueError, match="Invalid"):
+            persona.validate("scott", "../../etc/passwd")
 
 
 def test_validate_special_chars(tmp_path):
-    root = _make_temp_personas(tmp_path)
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
+    with patch.object(config.settings, "home_dir", root):
         for bad in ("alice bob", "alice;bob", "alice\x00bob", "A" * 33, ""):
             with pytest.raises(ValueError):
-                persona.validate(bad)
+                persona.validate(bad, "inara")
 
 
 def test_validate_allows_hyphen_underscore(tmp_path):
-    root = _make_temp_personas(tmp_path)
-    # Create a persona with hyphen and underscore in name
-    p = root / "my_ai-agent"
+    root = _make_home(tmp_path)
+    p = root / "my_user" / "persona" / "my-agent"
     p.mkdir(parents=True)
     (p / "IDENTITY.md").write_text("# My Agent")
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        assert persona.validate("my_ai-agent") == "my_ai-agent"
+    with patch.object(config.settings, "home_dir", root):
+        assert persona.validate("my_user", "my-agent") == ("my_user", "my-agent")
 
 
-def test_list_personas(tmp_path):
-    root = _make_temp_personas(tmp_path)
+def test_list_users(tmp_path):
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        names = persona.list_personas()
-    assert "alice" in names
-    assert "bob" in names
-    assert "incomplete" not in names   # no IDENTITY.md
+    with patch.object(config.settings, "home_dir", root):
+        users = persona.list_users()
+    assert "scott" in users
+    assert "holly" in users
 
 
-def test_persona_path_uses_contextvar(tmp_path):
-    root = _make_temp_personas(tmp_path)
+def test_list_user_personas(tmp_path):
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        persona.set_persona("alice")
-        assert persona.persona_path() == root / "alice"
-        persona.set_persona("bob")
-        assert persona.persona_path() == root / "bob"
+    with patch.object(config.settings, "home_dir", root):
+        names = persona.list_user_personas("scott")
+    assert "inara" in names
+    assert "alt" in names
+    assert "broken" not in names   # no IDENTITY.md
 
 
-def test_persona_path_explicit_name(tmp_path):
-    root = _make_temp_personas(tmp_path)
+def test_persona_path_uses_contextvars(tmp_path):
+    root = _make_home(tmp_path)
     import config, persona
-    with patch.object(config.settings, "personas_dir", root):
-        persona.set_persona("alice")
-        assert persona.persona_path("bob") == root / "bob"
+    with patch.object(config.settings, "home_dir", root):
+        persona.set_context("scott", "inara")
+        assert persona.persona_path() == root / "scott" / "persona" / "inara"
+        persona.set_context("holly", "tina")
+        assert persona.persona_path() == root / "holly" / "persona" / "tina"
+
+
+def test_persona_path_explicit_args(tmp_path):
+    root = _make_home(tmp_path)
+    import config, persona
+    with patch.object(config.settings, "home_dir", root):
+        persona.set_context("scott", "inara")
+        # Explicit args override the ContextVar
+        assert persona.persona_path("holly", "tina") == root / "holly" / "persona" / "tina"
+        # ContextVar unchanged
+        assert persona.persona_path() == root / "scott" / "persona" / "inara"
+
+
+def test_get_user_and_persona(tmp_path):
+    import persona
+    persona.set_context("scott", "inara")
+    assert persona.get_user() == "scott"
+    assert persona.get_persona() == "inara"
+    persona.set_context("holly", "tina")
+    assert persona.get_user() == "holly"
+    assert persona.get_persona() == "tina"