Improve README installation guidance

[hema-ai-tech]

What does this PR do?

Related issue

Before opening this PR

• I have checked that there is not already an open PR for this change.
• I have checked existing issues and discussions for relevant context.
• I have read the contributing guidelines.

Type of change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Test update
• Refactor or maintenance
• Performance improvement
• Build, CI, or release change

Affected areas

• Python SDK (memori/)
• TypeScript SDK (memori-ts/)
• Rust core or native bindings (core/)
• LLM providers or adapters
• Storage adapters or drivers
• Memory augmentation or recall
• Examples or integrations
• Documentation
• CI, packaging, or tooling

How was this tested?

• uv run pytest
• uv run ruff check .
• uv run ruff format --check .
• npm test from memori-ts/
• npm run lint from memori-ts/
• Integration tests
• Manual testing

Checklist

• I have kept this change focused and consistent with the existing architecture.
• I have added or updated tests where appropriate.
• I have updated documentation or examples for user-facing changes.
• This PR does not require live API keys for unit tests.
• This PR does not include generated artifacts, local databases, or cache files.
• I have called out any breaking changes, migration steps, or compatibility concerns below.

Notes for reviewers