Fix CI: remove Python 3.9, update extras to [dev] and [hf]

Python 3.9 dropped (requires-python >= 3.10). The [latent] extra
was removed in the packaging refactor — [dev] already includes [hf]
which provides torch + transformers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: SStas

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v4
@@ -25,7 +25,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -e ".[dev,latent]"
+          pip install -e ".[dev]"
 
       - name: Lint with ruff
         run: ruff check src/ tests/
@@ -46,7 +46,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -e ".[latent]"
+          pip install -e ".[hf]"
 
       - name: Run quickstart example
         run: python examples/quickstart.py