feat(files): implement file storage functionality with save, load, and list operations

README.md

@@ -41,6 +41,9 @@ A Go MCP server for capturing and retrieving thoughts, memory, and project conte
 | `recall_context` | Semantic + recency context block for injection |
 | `link_thoughts` | Create a typed relationship between thoughts |
 | `related_thoughts` | Explicit links + semantic neighbours |
+| `save_file` | Store a base64-encoded image, document, audio file, or other binary and optionally link it to a thought |
+| `load_file` | Retrieve a stored file by ID as base64 plus metadata |
+| `list_files` | Browse stored files by thought, project, or kind |
 | `backfill_embeddings` | Generate missing embeddings for stored thoughts |
 | `reparse_thought_metadata` | Re-extract and normalize metadata for stored thoughts |
 
@@ -112,6 +115,39 @@ Run `reparse_thought_metadata` to fix stale or inconsistent metadata by re-extra
 - If extraction fails for a thought, existing metadata is normalized and written only if it changes
 - Metadata reparse runs in parallel (4 workers); one failure does not abort the run
 
+## File Storage
+
+Use `save_file` to persist binary files as base64. Files can optionally be linked to a memory by passing `thought_id`, which also adds an attachment reference to that thought's metadata.
+
+```json
+{
+  "name": "meeting-notes.pdf",
+  "media_type": "application/pdf",
+  "kind": "document",
+  "thought_id": "optional-thought-uuid",
+  "content_base64": "<base64-payload>"
+}
+```
+
+Load a stored file again with:
+
+```json
+{
+  "id": "stored-file-uuid"
+}
+```
+
+List files for a thought or project with:
+
+```json
+{
+  "thought_id": "optional-thought-uuid",
+  "project": "optional-project-name",
+  "kind": "optional-image-document-audio-file",
+  "limit": 20
+}
+```
+
 **Automatic backfill** (optional, config-gated):
 
 ```yaml