Chore/rust ci reusable wrapper (#27)

* ci(rust): convert rust-ci.yml to thin wrapper (standards#174)

Replaces the per-repo `rust-ci.yml` copy with a 5-line wrapper invoking
the shared reusable workflow in `hyperpolymath/standards` (PR #174).

Pinned to PR #174's HEAD SHA `4fdf4314b4ab54269adbaff10e30e483b5e86845`; will resolve to standards/main
once #174 merges.

Estate audit found ~87 rust-ci.yml copies across the estate; this is
one of them. The reusable provides identical cargo check/clippy/fmt/test
behaviour with opt-in `enable_audit` + `enable_coverage` inputs.

Pattern precedent: standards#168 (governance-reusable) + downstream
wrappers absolute-zero#41 + tma-mark2#41.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(ci): switch CodeQL matrix to `actions` (no JS/TS in repo)

The default `javascript-typescript` matrix produced "no source
files" failures on every CodeQL run — this repo has no JS/TS.
Switched to `actions` extractor (scans workflow files which every
repo has). Per hypatia rule `codeql_language_matrix_mismatch`.

Refs hyperpolymath/gitbot-fleet#208 (estate sweep).

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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath