Remove tensorflow/keras files and the keras dependency (#15420)

Per discussion in #15418, these four files are not algorithms (they are
how-to-use scripts wrapping a deep-learning framework) and dragged in the
heavy keras/tensorflow dependency stack:

- computer_vision/cnn_classification.py
- dynamic_programming/k_means_clustering_tensorflow.py
- machine_learning/lstm/lstm_prediction.py
- neural_network/input_data.py (TF MNIST data loader; nothing imports it)

Also removes the now-orphaned machine_learning/lstm/ package (only
__init__.py + sample_data.csv, which served lstm_prediction.py).

Cleanups:
- Drop keras from pyproject.toml dependencies; regenerate uv.lock
  (removes absl-py, h5py, keras, ml-dtypes, namex, optree).
- Remove the pre-release libhdf5-dev install step from build.yml and
  sphinx.yml (it existed only because keras needs hdf5).
- Drop the four stale pytest --ignore entries in build.yml.
- Remove the four DIRECTORY.md entries and the empty Lstm heading.

Author: priya-sundaram-dev

.github/workflows/build.yml

@@ -20,12 +20,6 @@ jobs:
         with:
           python-version-file: .python-version
           allow-prereleases: true
-      # keras needs hdf5 on pre-release Python.
-      - run: |
-          if [ "$(python -c 'import sys; print(sys.version_info.releaselevel)')" != "final" ]; then
-            sudo apt-get update -qq
-            sudo apt-get install --yes libhdf5-dev
-          fi
       - run: uv sync --group=test
       - name: Run tests
         # opencv-python is gated out on 3.14t (no cp314t wheel yet), so skip the
@@ -41,16 +35,12 @@ jobs:
         # single file that imports it (quantum/q_fourier_transform.py) is skipped too.
         run: uv run --with=pytest-run-parallel pytest
           --iterations=8 --parallel-threads=auto --ignore-gil-enabled
-          --ignore=computer_vision/cnn_classification.py
           --ignore=computer_vision/flip_augmentation.py
           --ignore=computer_vision/harris_corner.py
           --ignore=computer_vision/mosaic_augmentation.py
           --ignore=data_compression/peak_signal_to_noise_ratio.py
           --ignore=digital_image_processing/
           --ignore=docs/conf.py
-          --ignore=dynamic_programming/k_means_clustering_tensorflow.py
-          --ignore=machine_learning/lstm/lstm_prediction.py
-          --ignore=neural_network/input_data.py
           --ignore=project_euler/
           --ignore=quantum/q_fourier_transform.py
           --ignore=scripts/validate_solutions.py

.github/workflows/sphinx.yml

@@ -33,12 +33,6 @@ jobs:
         with:
           python-version-file: .python-version
           allow-prereleases: true
-      # keras needs hdf5 on pre-release Python.
-      - run: |
-          if [ "$(python -c 'import sys; print(sys.version_info.releaselevel)')" != "final" ]; then
-            sudo apt-get update -qq
-            sudo apt-get install --yes libhdf5-dev
-          fi
       - run: uv sync --group=docs
       - uses: actions/configure-pages@v6
       - run: uv run sphinx-build -c docs . docs/_build/html

DIRECTORY.md

@@ -195,7 +195,6 @@
   * [Xtea](ciphers/xtea.py)
 
 ## [Computer Vision](computer_vision)
-  * [Cnn Classification](computer_vision/cnn_classification.py)
   * [Flip Augmentation](computer_vision/flip_augmentation.py)
   * [Gramian](computer_vision/gramian.py)
   * [Haralick Descriptors](computer_vision/haralick_descriptors.py)
@@ -474,7 +473,6 @@
   * [Floyd Warshall](dynamic_programming/floyd_warshall.py)
   * [Integer Partition](dynamic_programming/integer_partition.py)
   * [Iterating Through Submasks](dynamic_programming/iterating_through_submasks.py)
-  * [K Means Clustering Tensorflow](dynamic_programming/k_means_clustering_tensorflow.py)
   * [Knapsack](dynamic_programming/knapsack.py)
   * [Largest Divisible Subset](dynamic_programming/largest_divisible_subset.py)
   * [Longest Common Subsequence](dynamic_programming/longest_common_subsequence.py)
@@ -766,8 +764,6 @@
     * [Local Weighted Learning](machine_learning/local_weighted_learning/local_weighted_learning.py)
   * [Logistic Regression](machine_learning/logistic_regression.py)
   * [Loss Functions](machine_learning/loss_functions.py)
-  * Lstm
-    * [Lstm Prediction](machine_learning/lstm/lstm_prediction.py)
   * [Mab](machine_learning/mab.py)
   * [Mean Shift](machine_learning/mean_shift.py)
   * [Mfcc](machine_learning/mfcc.py)
@@ -1058,7 +1054,6 @@
     * [Swish](neural_network/activation_functions/swish.py)
   * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
   * [Convolution Neural Network](neural_network/convolution_neural_network.py)
-  * [Input Data](neural_network/input_data.py)
   * Optimizers
     * [Adagrad](neural_network/optimizers/adagrad.py)
     * [Adam Optimizer](neural_network/optimizers/adam_optimizer.py)