[FEATURE] Add issue templates, PR template, and contributing guidelines

[rayrishu19-wq]

Add structured GitHub issue templates (bug report & feature request), a pull request template, and a comprehensive contributing guide to standardize contributions and make the project more open-source friendly.

Problem Statement

Currently, the repository has no contribution guidelines or templates. Contributors don't have a standardized format for reporting bugs, requesting features, or submitting PRs. This makes it harder to maintain quality and consistency.

Proposed Solution

Add the following:

• Bug Report template (.github/ISSUE_TEMPLATE/bug_report.md) — Structured form for reporting bugs with reproduction steps, environment details, and screenshots
• Feature Request template (.github/ISSUE_TEMPLATE/feature_request.md) — Structured form for suggesting new features with acceptance criteria
• Pull Request template (.github/PULL_REQUEST_TEMPLATE.md) — Checklist-driven PR format with testing requirements and screenshot slots
• Contributing Guide (CONTRIBUTING.md) — Full guidelines covering coding standards, branch naming, commit conventions, and development workflow

Acceptance Criteria

• Bug report issue template with environment, reproduction steps, and screenshot sections
• Feature request issue template with problem statement and acceptance criteria
• PR template with type-of-change checkboxes and testing checklist
• Contributing guide with coding standards, branch naming, and commit format
• All templates follow conventional commits and GitHub best practices