V-L3-F1: prune CI noise — identify load-bearing vs governance workflows

[hyperpolymath]

Context

~20 workflows in this repo; most are governance scaffolding. The actually load-bearing ones for the Rust crate are: rust-ci, codeql, dependabot, release. Governance workflows shouldn't block the development flow.

What to do

• Identify the load-bearing set vs governance set.
• Move governance workflows into a reusable workflow library (probably in hyperpolymath/standards) and call them as a single wrapper from here.
• Confirm with gh pr checks that the count of required checks drops to a manageable handful.

Acceptance

• Required-check count documented
• Optional-check noise visible but not blocking