Update root README with architecture, providers, and onboarding links

[Copilot]

The issue asks to refresh the README with the new architectural direction, provider list, getting-started guidance, benchmark pointers, and a link to the wiki paper list. This PR updates the root README to include those items in a concise, scannable format.

• Architecture & components
  • Documented the Rust workspace layout across base/numerics, core algorithm, providers/storage, and tooling.
• Providers overview
  • Added a focused list of provider implementations with crate/feature references.
• Onboarding & references
  • Added getting-started steps and links to benchmark documentation plus the wiki paper list.

Example excerpt:

## Getting started

1. Install Rust using the toolchain in `rust-toolchain.toml`.
2. Build the workspace: `cargo build`.
3. Run tests: `cargo test`.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Update README</issue_title>
<issue_description>## Is your feature request related to a problem? Please describe.
We need to update the README with the following

Describe the solution you'd like

Add the following

• The new architectural direction.
• A list of providers
• Getting started
• pointers to benchmarks
• pointer to paper in Wiki
  </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Update README #739

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