fix(data): corrected 2026 split as verified in-force snapshot (issue #1035)

- 2026: rebuilt to 303 verified in-force laws, de-duplicated to one entry per
So hieu and validated against the official vbpl.vn database (was 318 with
80 duplicate + 37 fabricated/non-existent entries)
- 2026_01: preserve the original January 2026 release (318) for reproducibility
- metadata/2026_sources.json: per-document provenance links from 6 official and
reference sources (vbpl, vanban.chinhphu, congbao, vietlaw.quochoi, thuvienphapluat, luatvietnam)
- README: document the corrected 2026 split, the 2026_01 archive, and provenance

README.md

@@ -16,18 +16,23 @@ tags:
   - legislation
 pretty_name: Vietnamese Legal Corpus
 dataset_info:
-  splits:
-    - name: "2026"
-      num_examples: 318
-    - name: "2023"
-      num_examples: 208
-    - name: "2021"
-      num_examples: 110
+  - config_name: default
+    splits:
+      - name: "2026"
+        num_examples: 303
+      - name: "2026_01"
+        num_examples: 318
+      - name: "2023"
+        num_examples: 208
+      - name: "2021"
+        num_examples: 110
 configs:
   - config_name: default
     data_files:
       - split: "2026"
         path: data/2026-*
+      - split: "2026_01"
+        path: data/2026_01-*
       - split: "2023"
         path: data/2023-*
       - split: "2021"
@@ -47,9 +52,10 @@ This dataset contains Vietnamese legal documents including the Constitution, Cod
 
 | Split | Documents | Description |
 |-------|-----------|-------------|
-| 2021  | 110       | Original corpus with full text |
-| 2023  | 208       | Expanded corpus with processed text |
-| 2026  | 318       | Latest corpus with 2022-2025 laws |
+| 2021     | 110 | Original corpus with full text |
+| 2023     | 208 | Expanded corpus with processed text |
+| 2026_01  | 318 | Original 2026 release (Jan 2026) — superseded ([issue #1035](https://github.com/undertheseanlp/underthesea/issues/1035)) |
+| 2026     | 303 | Verified in-force snapshot (corrected, validated against vbpl.vn) |
 
 ### Document Types
 
@@ -86,6 +92,44 @@ The 2026 split includes laws passed by the 15th National Assembly:
 | content | string | Full text content |
 | content_length | int32 | Character count |
 
+## The `2026` split — corrected (issue #1035)
+
+An earlier build of the 2026 corpus was found to contain duplicated and mismatched entries
+([issue #1035](https://github.com/undertheseanlp/underthesea/issues/1035)): many documents carried
+a header *Số hiệu* that did not match their title, some titles were fabricated, and several bodies
+were near-duplicates of unrelated laws.
+
+The **`2026`** split has been **rebuilt as a verified in-force snapshot**: every entry is a currently
+in-force Law/Code (status *Còn hiệu lực* or *Hết hiệu lực một phần*), de-duplicated to one entry per
+*Số hiệu*, with full text re-sourced and validated against the official **vbpl.vn** national legal
+database (Ministry of Justice). The original January 2026 release is preserved unchanged as
+**`2026_01`** for reproducibility.
+
+| | `2026_01` (original) | `2026` (corrected) |
+|---|---|---|
+| Entries | 318 | **303** |
+| Duplicate Số hiệu | 80 | 0 |
+| Fabricated / non-existent | 37 | 0 |
+| Coverage of in-force laws | 188 | 304 |
+
+```python
+ds = load_dataset("undertheseanlp/UTS_VLC", split="2026")      # 303 verified in-force laws
+raw = load_dataset("undertheseanlp/UTS_VLC", split="2026_01") # 318, original Jan 2026 (issue #1035)
+```
+
+### Provenance — `metadata/2026_sources.json`
+
+Each corrected entry is cross-referenced to direct links from official and reference sources
+(≈8 links/entry on average), provided as a separate metadata file keyed by `id` / `doc_num`:
+
+| Field | Source | |
+|---|---|---|
+| `url_vbpl`, `url_vbpl_pdf`, `url_vbpl_luocdo` | vbpl.vn (Bộ Tư pháp) | OFFICIAL — full text, PDF, amendment map |
+| `url_vanban_chinhphu`, `url_vanban_pdf` | vanban.chinhphu.vn (Chính phủ) | OFFICIAL — document page, signed PDF |
+| `url_congbao_pdf` | congbao.chinhphu.vn (Công báo) | OFFICIAL — gazette PDF |
+| `url_quochoi` | vietlaw.quochoi.vn (Quốc hội) | OFFICIAL — full text |
+| `url_thuvienphapluat`, `url_luatvietnam` | thuvienphapluat.vn, luatvietnam.vn | reference (private) |
+
 ## Usage
 
 ```python
@@ -107,16 +151,19 @@ land_law = ds_2026.filter(lambda x: "Đất đai" in x["title"])
 
 ## Statistics
 
-| Metric | 2021 | 2023 | 2026 |
-|--------|------|------|------|
-| Documents | 110 | 208 | 318 |
-| Total Characters | ~14M | ~21M | ~24M |
-| Codes | 6 | 6 | 6 |
-| Laws | 104 | 202 | 312 |
+| Metric | 2021 | 2023 | 2026_01 | 2026 |
+|--------|------|------|------|------|
+| Documents | 110 | 208 | 318 | 303 |
+| Codes | 6 | 6 | 6 | 6 |
+| Laws | 104 | 202 | 312 | 297 |
 
 ## Data Source
 
-Documents were collected from [Thu Vien Phap Luat](https://thuvienphapluat.vn/), the official Vietnamese legal document database.
+The corrected `2026` split is sourced and verified against Vietnam's official legal databases —
+**vbpl.vn** (Cơ sở dữ liệu quốc gia về pháp luật, Ministry of Justice), **congbao.chinhphu.vn**
+(Official Gazette), **vanban.chinhphu.vn** (Government), and **vietlaw.quochoi.vn** (National
+Assembly) — with per-document provenance links in `metadata/2026_sources.json`. The original
+`2021`/`2023`/`2026_01` splits were collected from [Thu Vien Phap Luat](https://thuvienphapluat.vn/).
 
 ## References
 

data/2026-00000-of-00001.parquet

@@ -1,3 +1,3 @@
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-oid sha256:334f08ef06d09f2ab47827f353936c0b8d47ce994fe143792b9a80840f07e404
-size 9460623
+oid sha256:8f62f06bcf4345dd59de4f79074673b254081494ee9404928d9d932ca4fb94d3
+size 9722593

data/2026_01-00000-of-00001.parquet

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:334f08ef06d09f2ab47827f353936c0b8d47ce994fe143792b9a80840f07e404
+size 9460623