Added repo management: CI/CD, issue templates, dependabot

[nicolasbisurgi]

Summary

This PR sets up repository management infrastructure including automated releases, CI/CD, and community templates.

Changes

Automation

• CI workflow - Runs tests on PRs and pushes to master
• Release workflow - Label-controlled semantic versioning with automatic GitHub Releases
  Dependabot - Weekly updates for GitHub Actions and Python dependencies

Community

• Issue templates - Bug report, feature request, question
• PR template - Standardized PR format with release label guidance
• CONTRIBUTING.md - Developer setup and contribution guidelines

Code

• version - Added version 1.5.0 to rushti.py with --version flag support
• rushti.spec - PyInstaller build configuration

Documentation

• README.md - Updated executable section with download location, setup requirements, and build instructions

Housekeeping

• .gitignore - Python, IDE, linters, AI assistants
• Removed old build.yml (replaced by release workflow)

Release Strategy

• No label = no release
• release:patch → 1.5.0 → 1.5.1
• release:minor → 1.5.0 → 1.6.0
• release:major → 1.5.0 → 2.0.0