test: add unit tests for all 10 routers (92 total)

New test files:
- test_conversations.py — list/create/get/update/delete/delete-all, admin enforcement
- test_presets.py — list/create/update/delete, default preset protection
- test_profile.py — get/update/default, length validation
- test_models_router.py — list/ps/show/stats/search-status, connect errors
- test_completions.py — API key auth, FIM passthrough, streaming/blocking, errors
- test_search_route.py — explicit search flow, no results, stream errors
- test_memories.py — edit/search/stats endpoints, validation, admin enforcement

Update AGENTS.md with full test file coverage table and README.md

tests/test_presets.py

@@ -0,0 +1,128 @@
+import os
+from pathlib import Path
+
+from fastapi.testclient import TestClient
+
+import app
+import db
+from security import SESSIONS, PIN_ATTEMPTS, RATE_EVENTS
+
+
+def make_client(tmp_path: Path) -> TestClient:
+    os.environ["JARVISCHAT_ADMIN_PIN"] = "1234"
+    db.DB_PATH = tmp_path / "jarvischat-presets.db"
+    SESSIONS.clear()
+    PIN_ATTEMPTS.clear()
+    RATE_EVENTS.clear()
+    db.init_db()
+    return TestClient(app.app, raise_server_exceptions=False)
+
+
+def _admin_headers(client: TestClient) -> dict:
+    login = client.post("/api/auth/login", json={"pin": "1234"}, headers={"Origin": "http://testserver"})
+    sid = login.json()["session_id"]
+    return {"X-Session-ID": sid, "Origin": "http://testserver"}
+
+
+def _guest_headers(client: TestClient) -> dict:
+    sid = client.post("/api/auth/guest", headers={"Origin": "http://testserver"}).json()["session_id"]
+    return {"X-Session-ID": sid, "Origin": "http://testserver"}
+
+
+def test_list_presets_returns_defaults(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        resp = client.get("/api/presets", headers=_guest_headers(client))
+        assert resp.status_code == 200
+        presets = resp.json()
+        assert len(presets) >= 3
+        names = [p["name"] for p in presets]
+        assert "Coding Companion" in names
+
+
+def test_create_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        resp = client.post("/api/presets", json={"name": "My Preset", "prompt": "You are helpful."}, headers=headers)
+        assert resp.status_code == 200
+        data = resp.json()
+        assert data["name"] == "My Preset"
+        assert data["prompt"] == "You are helpful."
+
+        presets = client.get("/api/presets", headers=_guest_headers(client)).json()
+        assert any(p["name"] == "My Preset" for p in presets)
+
+
+def test_create_preset_requires_name_and_prompt(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        resp = client.post("/api/presets", json={"name": "", "prompt": ""}, headers=headers)
+        assert resp.status_code == 400
+
+        resp = client.post("/api/presets", json={"name": "Only Name"}, headers=headers)
+        assert resp.status_code == 400
+
+
+def test_update_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        create = client.post("/api/presets", json={"name": "Old", "prompt": "Old prompt."}, headers=headers)
+        preset_id = create.json()["id"]
+
+        update = client.put(f"/api/presets/{preset_id}", json={"name": "New", "prompt": "New prompt."}, headers=headers)
+        assert update.status_code == 200
+
+        presets = client.get("/api/presets", headers=_guest_headers(client)).json()
+        updated = next(p for p in presets if p["id"] == preset_id)
+        assert updated["name"] == "New"
+        assert updated["prompt"] == "New prompt."
+
+
+def test_update_preset_requires_fields(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        resp = client.put("/api/presets/nope", json={"name": "", "prompt": ""}, headers=headers)
+        assert resp.status_code == 400
+
+
+def test_delete_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        create = client.post("/api/presets", json={"name": "Temp", "prompt": "Temp."}, headers=headers)
+        preset_id = create.json()["id"]
+
+        delete = client.delete(f"/api/presets/{preset_id}", headers=headers)
+        assert delete.status_code == 200
+
+        presets = client.get("/api/presets", headers=_guest_headers(client)).json()
+        assert not any(p["id"] == preset_id for p in presets)
+
+
+def test_delete_default_preset_is_noop(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        headers = _admin_headers(client)
+        presets_before = client.get("/api/presets", headers=_guest_headers(client)).json()
+        default = next(p for p in presets_before if p["is_default"])
+
+        delete = client.delete(f"/api/presets/{default['id']}", headers=headers)
+        assert delete.status_code == 200
+
+        presets_after = client.get("/api/presets", headers=_guest_headers(client)).json()
+        assert any(p["id"] == default["id"] for p in presets_after)
+
+
+def test_guest_cannot_create_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        resp = client.post("/api/presets", json={"name": "Hack", "prompt": "Hack"}, headers=_guest_headers(client))
+        assert resp.status_code == 403
+
+
+def test_guest_cannot_update_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        resp = client.put("/api/presets/some-id", json={"name": "Hack", "prompt": "Hack"}, headers=_guest_headers(client))
+        assert resp.status_code == 403
+
+
+def test_guest_cannot_delete_preset(tmp_path: Path):
+    with make_client(tmp_path) as client:
+        resp = client.delete("/api/presets/some-id", headers=_guest_headers(client))
+        assert resp.status_code == 403