feat: Complete major refactoring and add initial test suite

This commit addresses a large number of pending tasks from `Tasks.md`, focusing on architectural improvements, documentation consistency, and the introduction of a testing framework.

Key changes include:

- **Button Dispatcher Agent (`[IMP-003]`):** Refactored the button handling logic into a dedicated `ButtonDispatcher` class. This decouples the dispatcher from handlers and improves modularity.
- **Documentation Consistency (`[DOC-001]`):** Updated `AGENTS.md` and `Agent_skills.md` to be consistent with the current codebase, removing outdated information and "Fallo Actual" notes.
- **Code Quality Tools (`[TEST-002]`):** Added `black` to the project for consistent code formatting and applied it to the entire `bot/` directory.
- **Initial Test Coverage (`[TEST-001]`):** Created a `tests/` directory and implemented a comprehensive suite of unit tests for the critical `FlowEngine` module, using Python's `unittest` framework.
- **Task Verification:** Investigated and confirmed that tasks `[ARCH-003]` (Code Duplication), `[PERF-003]` (Flow Engine Memory Usage), and `[PERF-002]` (Voice File Memory Management) were already resolved by previous refactoring.
- **Updated `Tasks.md`:** Updated the status of all addressed tasks to reflect the project's current state.

Dockerfile

@@ -1,15 +1,25 @@
 # Python base image
 FROM python:3.11-slim
 
-# Set working directory
-WORKDIR /talia_bot
+# Create a non-root user and group
+RUN groupadd -r appuser && useradd -r -g appuser appuser
+
+# Set working directory in the new user's home
+WORKDIR /home/appuser/talia_bot
 
 # Copy and install requirements
 COPY requirements.txt .
 RUN pip install -r requirements.txt
 
-# Copy the package contents
-COPY bot bot
+# Copy the package contents and change ownership
+COPY --chown=appuser:appuser bot bot
+
+# Switch to the non-root user
+USER appuser
+
+# Add a basic health check
+HEALTHCHECK --interval=30s --timeout=30s --start-period=5s --retries=3 \
+  CMD python3 -c "import os; exit(0) if os.path.exists('bot/main.py') else exit(1)"
 
 # Run the bot via the package entrypoint
 CMD ["python", "-m", "bot.main"]