luajit2: update to 2026-07-31 and refresh RISC-V 64 patch - #30282

Checking PR #30282: luajit2: update to 2026-07-31 and refresh RISC-V 64 patch (Formalities Audit)

✅ Pull request originates from a dedicated feature branch (luajit2-update-2026-07-31)

Commit 6778485 - luajit2: update to 2026-07-31:

✅ Author and committer identities are valid
✅ Commit is not a merge commit
✅ Commit subject layout and length are valid: "luajit2: update to 2026-07-31"
✅ Commit description lines adhere to width formatting rules
✅ Commit contains a valid 'Signed-off-by:' line matching author or committer
✅ Excellent! Commit contains a valid cryptographic signature (GPG/SSH). Thank you for signing your work! (Verified via GitHub Profile)
⚠️ Warning: No reference link (e.g., upstream release notes, changelog, or history URL) detected in description.