[Meta] Update URLs after StarTrail-org transfer: README, badges, PyPI, docs, workflows

[elJayAdvisor]

[Meta] Update URLs after StarTrail-org transfer: README, badges, PyPI, docs, workflows

Summary
The repository was recently transferred from yichuan-w/LEANN to StarTrail-org/LEANN. Several URLs throughout the project still reference the old namespace, which is a supply-chain hygiene concern.

Stale References

• README.md: Clone examples and badge URLs still point to yichuan-w/LEANN
• PyPI project URLs: Package metadata may reference old namespace
• docs/RELEASE.md: Workflow links and release instructions reference old repo
• llms.txt: Contains stale namespace references
• Star history links: GitHub badges/images point to old namespace

Why This Matters
External tooling that monitors security updates, dependency managers, and integrations rely on stable, consolidated URLs. When stale pointers to the old namespace persist:

• Security advisory tooling may not properly track the project
• Dependency monitors may miss updates
• External integrations could resolve to the wrong namespace

Suggested Fix
Update all user-facing URLs to consolidate on StarTrail-org/LEANN:

1. Clone instructions in README
2. Badge references
3. PyPI project URLs
4. Workflow and docs links
5. Community links (llms.txt, etc.)

This is low-effort follow-up consolidation after the transfer. Thank you for the work you're doing on LEANN — the MLSys 2026 Best Paper award is well-deserved.