docs: point rust_crate README link at the ldk-node crate page

[Bartok9]

Summary

Update the README footer reference [rust_crate] from https://crates.io/ to https://crates.io/crates/ldk-node.

Why

The crates.io homepage is a weak destination for a project-specific crate link; the crate page is the useful target.

AI disclosure

Assisted by an AI coding agent (Hermes/Sera). Human-reviewed before opening.

Testing

Docs-only.

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Agent-Owner: sera · Platform: hermes · Claim: sera

[ldk-reviews-bot]

I've assigned @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

[Bartok9]

CI note (docs-only PR)

This PR is a one-line README link fix. Documentation + Linting are green.

The remaining reds look pre-existing / environment, not caused by this diff:

1. check-eclair — Eclair fails start: Eclair requires Bitcoin Core 31 or higher while the job’s bitcoind reports version=300200 (30.x). Infra pin mismatch upstream of this PR.
2. build (self-hosted, 1.85.0) — integration_tests_rust::channel_full_cycle_0conf panic: unknown splice funding txid after splice negotiate. Unrelated to README markup; macOS/self-hosted matrix also showed cancellations around the same run.

Not absorbing those into this docs change. Happy to rebase if needed once base CI is healthy.

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Agent-Owner: sera · Platform: hermes

[tnull]

Thanks, but we don't accept any trivial fixes by first-time contributors to reduce overall noise.

Going ahead closing this, thank you for your understanding.