Add static task categories with default Medium and badge rendering

[Copilot]

This PR implements FR-01 by adding predefined task categories (High, Medium, Low) at task creation time, defaulting to Medium when omitted or invalid. It also surfaces the category in the task list as a badge under each task title.

• Frontend: task creation + category UX

  • Added category selector to the create-task form (High|Medium|Low) with Medium preselected.
  • Sends category with create requests.
  • Uses a shared DEFAULT_CATEGORY constant to avoid category drift.

• Frontend: task list rendering

  • Renders category badge below task title (category-high, category-medium, category-low).
  • Switched task item rendering from interpolated innerHTML to DOM node construction for user-provided fields.
  • Added accessible action labels, including state-aware complete/incomplete labeling.

• Backend: category normalization + input constraints

  • Added centralized category normalization (normalizeCategory) for create/update flows.
  • Persists category on create; preserves valid values and falls back to Medium otherwise.
  • Added non-empty trimmed title validation for create and update; update now trims title before persisting.

• Styling

  • Added category badge styles and improved contrast for category text.
  • Reduced duplicated input/select styling rules.

// backend/controllers/tasksController.js
const VALID_CATEGORIES = ['High', 'Medium', 'Low'];

function normalizeCategory(category) {
  return VALID_CATEGORIES.includes(category) ? category : 'Medium';
}

const { title, category = 'Medium' } = req.body;
if (typeof title !== 'string' || title.trim() === '') {
  return res.status(400).json({ message: 'Title is required and cannot be empty' });
}

const newTask = {
  id: uuidv4(),
  title: title.trim(),
  category: normalizeCategory(category)
};

Original prompt

Funcionalidad: Categorización Estática de Tareas (FR-01)
Descripción: Permitir al usuario asignar una categoría predefinida a cada tarea al momento de su creación. Utiliza las categorías (High, Medium y Low), muéstralas como un badge debajo del título y si no se selecciona una categoría, utiliza médium por defecto.

[Chronological Review: The conversation began with a user request to analyze the project structure and execute necessary commands to run the application using Docker Compose. Following this, the user specified a functionality requirement for static task categorization, detailing how tasks should be assigned predefined categories (High, Medium, Low) with a default of Medium if none is selected.]

[Intent Mapping:

1. "Analiza la estructura del proyecto y ejecuta los comandos necesarios para levantar la aplicación utilizando Docker Compose." - User wants to analyze the project structure and run the application with Docker Compose.
2. "Funcionalidad: Categorización Estática de Tareas (FR-01)" - User specifies a feature requirement for task categorization with details on how it should function.]

[Technical Inventory:

• Docker Compose: Tool for defining and running multi-container Docker applications.
• Static Task Categorization: Feature involving predefined categories for tasks, with specific UI requirements for displaying these categories.]

[Code Archaeology: No specific files or code changes were discussed yet, but the feature request implies potential modifications to task management components.]

[Progress Assessment:

• Completed Tasks: None yet, as the conversation is still in the planning phase.
• Partially Complete Work: The analysis of the project structure and the feature specification for task categorization are in progress.]

[Context Validation: All necessary context for continuing the work on Docker Compose setup and task categorization feature is captured.]

[Recent Commands Analysis:

• Last Agent Commands: The user requested an analysis of the project structure and execution of Docker Compose commands.
• Tool Results Summary: No tool results were returned yet as the commands have not been executed.
• Pre-Summary State: The agent was preparing to analyze the project structure and implement the Docker Compose commands when the token budget was exceeded.
• Operation Context: These commands are essential for setting up the development environment and ensuring the application runs correctly, which aligns with the user's goal of implementing the task categorization feature.]

1. Conversation Overview: - Primary Objectives: - "Analiza la estructura del proyecto y ejecuta los comandos necesarios para levantar la aplicación utilizando Docker Compose." - "Funcionalidad: Categorización Estática de Tareas (FR-01)" - User aims to implement a feature for categorizing tasks. - Session Context: The conversation has focused on setting up the application environment and defining a new feature for task management. - User Intent Evolution: The user started with a technical setup request and then moved to a specific feature requirement.

2. Technical Foundation:

• Docker Compose: Tool for managing multi-container Docker applications, essential for running the application.
• Static Task Categorization: Feature requiring UI elements for task categorization with specific default behaviors.

3. Codebase Status:

• No specific files or code changes have been discussed yet, but the task categorization feature will likely involve modifications to task-related components.

4. Problem Resolution:

• Issues Encountered: None reported yet as the setup and feature implementation are still in the planning phase.
• Solutions Implemented: No solutions have been implemented yet.
• Debugging Context: No debugging efforts have been initiated.
• Lessons Learned: Insights will emerge as the project progresses.

5. Progress Tracking:

• Completed Tasks: None completed yet.
• Partially Complete Work: Analysis of project structure and feature specification for task categorization are ongoing.

6. Active Work State:

• Current Focus: Analyzing the project structure and preparing to execute Docker Compose commands.
• Recent Context: The user has requested to analyze the project and implement a feature for task categorization.
• Working Code: No specific code snippets have been discussed yet.
• Immediate Context: The agent was preparing to execute commands related to Docker Compose when the token budget was exceeded.

7. Recent Operations:

• Last Agent Commands: User requested analysis of the project structure and execution of Docker Compose commands.
• Tool Results Summary: No results returned yet as commands have not been executed.
• Pre-Summary State: The agent was actively preparing for project analysis and Docker setup.
• Operation Context: These commands are crucial for establishing the development environment and supporting the task categorization feature.

8. Continuation Plan:
   ...

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