updated documentation

docs/services/memory-service.md

@@ -34,7 +34,7 @@ service to generate and store a vector in Qdrant.
 ```
 src/
 ├── db/
-│   ├── index.js       # SQLite connection + initialization
+│   ├── index.js       # SQLite connection + initialization + migrations
 │   └── schema.js      # Table definitions, indexes, FTS5, triggers
 ├── episodic/
 │   └── index.js       # Session + episode CRUD, FTS search, embedding write path
@@ -49,12 +49,29 @@ src/
 
 Five core tables:
 
-- **sessions** — top-level conversation containers, identified by an `external_id`
+- **sessions** — top-level conversation containers, identified by an `external_id` and optional `name`
 - **episodes** — individual exchanges (user message + AI response) tied to a session
 - **entities** — named things the system learns about (people, places, concepts)
 - **relationships** — directional labeled links between entities
 - **summaries** — condensed episode groups for efficient context retrieval
 
+### Migrations
+
+Schema changes that cannot be expressed in `CREATE TABLE IF NOT EXISTS` are applied
+as migrations in `db/index.js` at startup, wrapped in try/catch to safely ignore
+already-applied changes:
+
+```js
+try {
+    db.exec(`ALTER TABLE sessions ADD COLUMN name TEXT`);
+} catch {
+    // Column already exists — safe to ignore on subsequent startups
+}
+```
+
+Current migrations:
+- `ALTER TABLE sessions ADD COLUMN name TEXT` — adds display name to sessions
+
 ### FTS5 Full-Text Search
 
 An `episodes_fts` virtual table enables keyword search across all episodes.
@@ -144,9 +161,14 @@ Entities and relationships are stored in SQLite with two key constraints:
 | Method | Path | Description |
 |---|---|---|
 | POST | /sessions | Create a new session |
+| GET | /sessions | Get paginated list of all sessions |
 | GET | /sessions/:id | Get session by internal ID |
 | GET | /sessions/by-external/:externalId | Get session by external ID |
-| DELETE | /sessions/:id | Delete session (cascades to episodes + summaries) |
+| PATCH | /sessions/by-external/:externalId | Update session name |
+| DELETE | /sessions/by-external/:externalId | Delete session (cascades to episodes + summaries) |
+
+> Route ordering matters in Express: `by-external/:externalId` must be defined before
+> `/:id` to prevent the literal string `by-external` being captured as an ID parameter.
 
 **POST /sessions body:**
 ```json
@@ -156,6 +178,20 @@ Entities and relationships are stored in SQLite with two key constraints:
 }
 ```
 
+**PATCH /sessions/by-external/:externalId body:**
+```json
+{
+  "name": "My Renamed Session"
+}
+```
+
+Returns the updated session object. `name` is required and must be non-empty.
+
+**DELETE /sessions/by-external/:externalId**
+
+Returns `204 No Content` on success. Cascades to delete all associated episodes
+and summaries via SQLite `ON DELETE CASCADE`.
+
 ### Episodes
 
 | Method | Path | Description |