add annotation doc

Author: githubering182

README.md

@@ -30,6 +30,7 @@ See [docs/](/docs) for manuals and walkthroughs:
 - [Goals](/docs/goals.md)
 - [Statistics](/docs/statistics.md)
 - [Downloads](/docs/downloads.md)
+- [Annotation](/docs/annotation.md)
 
 ## ⚙️ Architecture
 

docs/annotation.md

@@ -0,0 +1,63 @@
+# 🧾 Annotation
+When exporting your dataset—or just annotations, a structured JSON file is generated.
+
+It contains metadata for all files matching the current filters and their annotations—without media.
+
+## 🧬 Example Structure
+
+```json
+[
+    {
+        "id": "6848a6709aeaf5eb62cf01a8",
+        "related_duplicates": 0,
+        "attributes": [
+            {
+                "uid": "f35846ca-0c7e-4120-8225-9204b054bb1a",
+                "attributes": [
+                    [16, 0, "type_1", ""],
+                    [18, 0, "subtype_2", ""],
+                    [20, 1, "r", ""]
+                ]
+            }
+        ],
+        "author_name": "Curator",
+        "validator_name": "Curator",
+        "file_name": "6788191feac1f1a81ab2fadd.webp",
+        "file_type": "image",
+        "status": "a",
+        "upload_date": "2025-06-10 21:41",
+        "update_date": "2025-06-10 21:41",
+        "rebound_project": null,
+        "rebound": null
+    }
+]
+```
+
+Where:
+- **id** - is generated file id by which the file could be found in the system
+- **related_duplicates** - number of duplicates associated to this file
+- **attributes** - list of attribute (label) groups with annotated data
+- **author_name** - the username of user who uploaded this file
+- **validator_name** - the username of user who validated this file
+- **file_name** - original file name
+- **file_type** - media type (image/video)
+- **status** - validation status, `a - accepted`, `d - declined`, `v - waits for validation`
+- **upload_date** - file upload date
+- **update_date** - file update date
+- **rebound_project** - project / bucket where the file is located in case of file transfer
+- **rebound** - file project / bucket (in terms of storage system)
+
+## Accessing a file
+
+Since the project in **wip** state there are some temprorary solutions.
+We have a situation when we want to move some files to other project.
+Since proper object movement is not implemented yet we could use a trick to just associate
+file project to the new one but since file is stored in original bucket we have to specify it.
+
+Using orm / db model you might encounter **rebound** field as well.
+This one is proper and intentional and used for rebounding file lookup in cases when uploaded file marked as duplicated one.
+Since we use best quality for all the duplicates this best one has related_duplicates count and all the duplicats have this rebound field set with id of "original" file.
+
+So in order to access a file you must follow this: `project_<rebound_project_id | project_id>/<rebound_id | file_id>` object lookup.
+
+When exporting datasets, rebound is resolved internally. Each exported entry is final, and you can access it directly via its id and extension (from file_name).

docs/downloads.md

@@ -36,3 +36,9 @@ In that case, the row turns red and the **result message** column shows what wen
 ## ➕ Only New Files
 When re-downloading later (e.g., the next day), you might want to include only new files.
 Enable the `not downloaded before` flag to skip any files already included in past archives (based on the filters).
+
+---
+
+### ✅ Next Step
+
+[Annotation](/docs/annotation.md)