### Summary
Aligns Go and Python error codes/messages so both backends honor the
same RESTful API contract, removing implementation-specific error leaks
(MySQL errors, `ValueError`, `AttributeError`, Gin validator format) in
favor of clean business error codes.
**Chat list** — invalid `orderby` now returns code 101 (was: raw Python
`AttributeError` code 100); invalid `page`/`page_size` values fall back
to defaults (was: raw `ValueError`/`ProgrammingError` code 100).
**Dataset create/update/delete** — adds UUID validation (101),
extra-field rejection (101), duplicate-id detection (101), content-type
/ JSON-syntax / object-shape checks (101), and "lacks permission" for
nonexistent datasets (IDOR). Create auto-deduplicates dataset names.
Pagerank updates tolerate a missing ES index. List response includes
`parser_config` and `pagerank`.
**Session list/update** — adds filtering, sorting, and pagination
support. Empty payloads are valid no-ops. Authorization errors map to
code 109.
**Chunk list** — doc object uses Python key names (`chunk_count`,
`dataset_id`, `chunk_method`, run text status). Add validates list
element types.
**Document update** — adds `chunk_method` alias, pydantic-style Field
error messages, metadata index auto-create with refresh, and "These
documents do not belong to dataset" messages. List validates
`metadata_condition` and reports ownership errors for unmatched name/id
filters.
**Search completion** — `kb_ids` ownership failure returns code 102
instead of 109.
Released 31 contract tests from `GO_ONLY_SKIPS` (all verified passing on
both Go and Python backends with real LLM keys).
### What problem does this PR solve?
| # | Method | Endpoint | Description | Git Equivalent |
|---|--------|----------|-------------|----------------|
| 1 | `POST` | `/api/v1/{prefix}/{folder_id}/commits` | Create a
snapshot commit with file changes (add/modify/delete/rename) | `git add`
+ `git commit` |
| 2 | `GET` | `/api/v1/{prefix}/{folder_id}/commits` | List commit
history (paginated) | `git log` |
| 3 | `GET` | `/api/v1/{prefix}/{folder_id}/commits/{commit_id}` | Get
commit detail with file changes | `git show` |
| 4 | `GET` | `/api/v1/{prefix}/{folder_id}/commits/{commit_id}/files` |
List file changes in a commit | `git show --name-status` |
| 5 | `GET` |
`/api/v1/{prefix}/{folder_id}/commits/diff?from=...&to=...` | Compare
two commits and return differences | `git diff` |
| 6 | `GET` | `/api/v1/{prefix}/{folder_id}/changes` | Get uncommitted
changes (add/modify/delete) | `git status` |
| 7 | `GET` | `/api/v1/{prefix}/{folder_id}/commits/{commit_id}/tree` |
Get the folder tree snapshot at commit time | `git ls-tree` |
| 8 | `GET` |
`/api/v1/{prefix}/{folder_id}/commits/{commit_id}/files/{file_id}/content`
| Get a file's content as it existed in a specific commit | `git show
HEAD:file` |
| 9 | `GET` | `/api/v1/{prefix}/{file_id}/versions` | Get version
history for a specific file across all commits | `git log -- file` |
Where `{prefix}/{id}` can be:
- `folders/{folder_id}` — direct folder access
- `workspaces/{workspace_id}` — alias of `folders/{folder_id}`
- `datasets/{dataset_id}` — resolves to the dataset's folder
- `memories/{memory_id}` — resolves to the memory's folder
- `skills/{skill_id}` — resolves to the skill's folder
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Documentation Update
### What problem does this PR solve?
extend restful api suite
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Other (please describe): test
### What problem does this PR solve?
extend restful api suite
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Other (please describe): test
### What problem does this PR solve?
add new testing suite for the new restful api endpoints meant to replace
http and web api tests
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Other (please describe): test
