CI: validate-docs.sh breaks on every release (version mismatch)

[pszymkowiak]

Problem

The scripts/validate-docs.sh CI check requires that README.md, CLAUDE.md, and ARCHITECTURE.md all mention the exact version from Cargo.toml. Since release-please bumps Cargo.toml automatically but not the docs, this check fails after every release.

Current state: Cargo.toml is at 0.28.2, but README.md still says 0.28.0.

Impact

• validate job fails on every PR until someone manually updates the version strings in 3 docs files
• This is a false positive — the docs don't need to track the exact patch version

Proposed fix

Either:

1. Remove version check from docs — don't require exact version match in README/CLAUDE.md/ARCHITECTURE.md
2. Use a version placeholder — e.g. rtk X.Y.Z and let release-please update it
3. Only check major.minor — allow patch version mismatch

Option 1 is simplest and avoids future breakage.

[pszymkowiak]

Fixed in v0.30.0 — commit 6e61c24 removes version check from validate-docs CI.