Improve README content and add new sections

[AAdewunmi]

Summary

Improve the README so it better presents Trackly’s MVP scope, setup path, verification evidence, deployment readiness, and reviewer-facing project context.

Changes

• Expanded README content for the Trackly SaaS MVP.
• Added clearer sections for product scope, technical stack, demo data, local setup, CI verification, deployment readiness, and documentation coverage.
• Clarified the deterministic demo accounts and seeded data workflow.
• Improved language around authenticated workflows, job application tracking, notes, dashboard metrics, DRF API access, and deterministic job-fit insights.
• Added stronger release-readiness framing for reviewers.

Behaviour

No application behaviour changes.

This is a documentation-only update. Runtime code, models, views, templates, API endpoints, migrations, and tests are unchanged.

Why

The README is the main entry point for reviewers, contributors, and future deployment checks. It should explain not only what Trackly does, but how to run it, verify it, demo it, and understand the engineering evidence behind the MVP.

Validation

• Reviewed README content against the current project structure and documented workflows.
• Checked alignment with existing docs, including local setup, CI, deployment, API, architecture, and final verification guidance.
• Confirmed the update reflects the current Docker, Django, PostgreSQL, DRF, NLP, and CI setup.

Result

The README now gives a clearer and more complete overview of Trackly as a production-minded Django SaaS MVP, including how to run it locally, seed demo data, verify the build, and understand the project’s release-readiness story.

Notes

No database changes, dependency changes, or deployment configuration changes are included in this PR.