chore: import upstream snapshot with attribution

docs/en/tutorials/classify.rst

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+========================
+Text Classification
+========================
+
+Text classification is a fundamental NLP task that assigns predefined categories to text instances. It is widely applied in multiple scenarios:
+
+- **Sentiment analysis**: Determine emotional polarity (positive/negative/neutral) in reviews or comments
+- **Topic labeling**: Categorize news articles or documents by subject
+- **Spam detection**: Identify unsolicited emails/messages
+- **Intent recognition**: Classify user queries in dialog systems
+- **Question answering**: Determine answerability of questions
+
+Key technical challenges include:
+1. Variable text lengths (from phrases to documents)
+2. Multilingual and cross-domain generalization
+3. Discrepancies in label systems across domains
+4. Class imbalance issues
+
+Common solutions involve:
+- Data cleaning and preprocessing
+- Feature engineering (TF-IDF, embeddings)
+- Model selection (from traditional ML to deep learning)
+- Hyperparameter tuning and ensemble methods

docs/en/tutorials/embedding.rst

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+========================
+Word Vectors
+========================

docs/en/tutorials/general_dialogue.rst

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+========================  
+General Conversation  
+========================

docs/en/tutorials/lexical_analysis.rst

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+========================
+Lexical Analysis
+========================
+
+Lexical Analysis (词法分析)
+--------------------------
+
+Lexical analysis is the process of converting a character sequence into a token sequence. It is the first phase of compilation and also the foundation of natural language processing.
+
+Main Tasks:
+1. Tokenization (分词)
+2. Removing whitespace/comments
+3. Tracking line numbers
+4. Generating symbol tables
+
+Example code:
+```python
+# This is a comment
+x = 123
+if (x > 0) {
+    print("Positive")
+}
+```
+
+Mathematical Representation:
+$$ T = Lex(S) $$
+Where $S$ is the input string and $T$ is the output token sequence.
+
+See details in [link](#lexer-implementation). For HTML tags: <div class="important"></div>

docs/en/tutorials/machine_translation.rst

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+========================
+Machine Translation
+========================

docs/en/tutorials/ner.rst

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+========================
+Sequence Labeling
+========================

docs/en/tutorials/overview.rst

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+============
+Overview
+============
+
+Case Collections
+----------
+
+  - Word Vectors
+
+    - `Improve Model Performance with Pre-trained Word Vectors <https://aistudio.baidu.com/aistudio/projectdetail/1535355>`_
+
+  - Text Classification
+
+    - `Text Classification Based on LSTM and Other RNN Networks <https://aistudio.baidu.com/aistudio/projectdetail/1283423>`_
+    - `Text Classification Using Pre-trained Models <https://aistudio.baidu.com/aistudio/projectdetail/1294333>`_
+    - `Custom Dataset for Text Multi-classification Task <https://aistudio.baidu.com/aistudio/projectdetail/1468469>`_
+
+  - Information Extraction
+
+    - `Express Bill Information Extraction with BiGRU-CRF Model <https://aistudio.baidu.com/aistudio/projectdetail/1317771>`_
+    - `Optimizing Express Bill Extraction with Pre-trained Model ERNIE <https://aistudio.baidu.com/aistudio/projectdetail/1329361>`_
+    - `Relation Extraction <https://aistudio.baidu.com/aistudio/projectdetail/1639963>`_
+    - `Event Extraction <https://aistudio.baidu.com/aistudio/projectdetail/1639964>`_
+
+  - Machine Reading Comprehension
+
+    - `Machine Reading Comprehension Using Pre-trained Models <https://aistudio.baidu.com/aistudio/projectdetail/1339612>`_
+
+  - Dialogue
+
+    - `Multi-skill Dialogue <https://aistudio.baidu.com/aistudio/projectdetail/1640180>`_
+
+  - Text Generation
+
+    - `Automatic Couplet Generation with Seq2Seq Model <https://aistudio.baidu.com/aistudio/projectdetail/1321118>`_
+    - `Intelligent Poetry Generation with ERNIE-GEN Model <https://aistudio.baidu.com/aistudio/projectdetail/1339888>`_
+
+  - Time Series Prediction
+
+    - `COVID-19 Case Prediction Using TCN Network <https://aistudio.baidu.com/aistudio/projectdetail/1290873>`_
+
+    More tutorials available at `PaddleNLP on AI Studio <https://aistudio.baidu.com/aistudio/personalcenter/thirdview/574995>`_

docs/en/tutorials/reading_comprehension.rst

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+========================
+Reading Comprehension
+========================

docs/en/tutorials/semantic_matching.rst

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+========================
+Semantic Matching
+========================

docs/en/tutorials/text_generation.rst

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+========================
+Text Generation
+========================