Refresh project documentation and prepare version 1.3.0

[Niox1337]

New readers can install the package, run a complete first example and follow tensor elements across operations from the README. A new documentation page gives LLMs a reusable teaching prompt, verified API boundaries and runnable beginner lesson templates.

This prepares version 1.3.0, updates the package description and documentation links, and records the features added since 1.2.0. The provenance diagram is generated with the public API. Documentation now reports the real package version and describes SVG/text export accurately.

Validation:

• README and guide Python examples executed, including interactive and static fallback paths.
• Strict Sphinx build passed. Desktop and mobile documentation previews inspected.
• Local suite: 1,812 passed, with 136 JAX/TensorFlow cases skipped in the base interpreter. The backend CI matrix verifies each framework separately.
• Wheel and sdist installation checks passed for version 1.3.0, including 1,744 tests in the isolated environment.

Closes #113