fix(github): penalize certificate assets as metadata

[risu729]

Summary

• treat .cert and .cer release assets like other metadata/signature files during asset scoring
• extend the existing metadata penalty test to cover certificate assets

Extracted from #10103 so this metadata scoring fix can land separately from the x86 fallback work. The .cer extension was added from review feedback because it is another common certificate asset extension.

Tests

• cargo test test_metadata_penalty
• cargo fmt --check

[gemini-code-assist]

Code Review

This pull request adds support for recognizing and penalizing .cert certificate files in the asset matcher, ensuring they are not incorrectly prioritized over actual binaries. It also adds corresponding unit tests to verify this behavior. The reviewer suggested also adding .cer as it is another common certificate extension.

[greptile-apps]

Greptile Summary

This PR adds .cert and .cer as penalized metadata extensions in the GitHub asset scorer, consistent with the already-penalized .crt, .pem, .key, and .pub entries.

• Asset penalty logic (asset_matcher.rs ~line 420): .cert and .cer are inserted adjacent to .crt, preserving the existing ordering convention.
• Test coverage: test_metadata_penalty is extended with both new extensions, each verified to score below the primary tarball asset.

Confidence Score: 5/5

A two-line addition to an extension allowlist with direct test coverage — no functional risk.

The change is a minimal, self-contained addition of two certificate file extensions to an existing penalty list. The logic and placement are consistent with surrounding entries (.crt, .pem, .key), and both new extensions are exercised in the updated test.

No files require special attention.

Important Files Changed

Filename	Overview
src/backend/asset_matcher.rs	Adds .cert and .cer to the metadata penalty list alongside the existing .crt/.pem entries, with matching test assertions for both new extensions.

_{Reviews (2): Last reviewed commit: "fix(github): penalize cer assets as meta..." | Re-trigger Greptile}