feat: add task template feature

[codefromlani]

closes #47

This PR adds full support for task templates in tix

Changes:

• TemplateStorage class for JSON-based storage of task templates.
• tix template save <task_id> <name> command to save a task as a template.
• tix template list command to display all saved templates.
• tix add --template <name> creates tasks from templates.

This enables quick reuse of common task patterns for faster task creation.

• Documentation: Updated README with usage examples for template commands.
• Tests:
  - Pytest coverage for TemplateStorage save, load, and list.
  - CLI tests for template save, template list, and add --template.

Sample:

[Valentin-v-Todorov]

@codefromlani Thanks for the PR. However there are some missing core functionality:

❌ No tix add --template command to actually USE templates
❌ The load_template() method returns a dict, not a Task object
❌ No way to create tasks from templates

What's done:
✅ TemplateStorage class for managing templates
✅ tix template save <task_id> command
✅ tix template list command
✅ Templates stored in ~/.tix/templates/

[codefromlani]

@codefromlani Thanks for the PR. However there are some missing core functionality:

❌ No tix add --template command to actually USE templates ❌ The load_template() method returns a dict, not a Task object ❌ No way to create tasks from templates

What's done: ✅ TemplateStorage class for managing templates ✅ tix template save <task_id> command ✅ tix template list command ✅ Templates stored in ~/.tix/templates/

I’m already working on those and will push the changes soon

[Valentin-v-Todorov]

@codefromlani Please let me know when the PR is ready for review ✌️

[Valentin-v-Todorov]

@codefromlani Do you need some help ? I will be happy to assist ? :)

[codefromlani]

@Valentin-v-Todorov
Hi, thanks for reaching out. I’ve noticed that the main branch currently has some issues, a few tests are failing, and some references to context remain even though it seems to have been removed from the project.

I’ll work on the task templates once the branch is updated and stable. Thanks