rust-guard: add MinIntegrity::from_policy_str to unify integrity parsers + extract_repo_from_item tests

[Copilot]

integrity_level_rank and integrity_for_level both contained an identical 4-way case-insensitive if/else chain parsing integrity level strings. Adding a new level required updating both in sync with no compiler enforcement.

Changes

• MinIntegrity::from_policy_str(level: &str) -> Option<Self> — adds the reverse direction of as_str(). Trims whitespace, case-insensitive match, returns None for unrecognised values.

impl MinIntegrity {
    pub(crate) fn from_policy_str(level: &str) -> Option<Self> { ... }
}

• integrity_level_rank / integrity_for_level refactored — both now delegate to match MinIntegrity::from_policy_str(level). The parsing logic lives in exactly one place; exhaustive match means the compiler will flag any missed case site when a new variant is added.

• MinIntegrity::from_policy_str unit tests — known levels, case insensitivity, whitespace trimming, unknown input (None), and roundtrip with as_str().

• extract_repo_from_item unit tests — previously untested despite driving repo attribution for every labeled item. New tests cover all five lookup strategies (direct full_name, repository.full_name, base.repo.full_name, head.repo.full_name, URL parsing fallback) plus priority ordering and the empty fallback.

[Copilot]

Pull request overview

This PR reduces duplication in the rust-guard policy integrity parsing by centralizing string-to-MinIntegrity conversion, and it adds missing unit test coverage for extract_repo_from_item, which influences repo attribution for labeled items.

Changes:

• Added MinIntegrity::from_policy_str(&str) -> Option<MinIntegrity> to provide a single canonical, trimmed, case-insensitive parser for policy integrity tokens.
• Refactored integrity_level_rank and integrity_for_level to delegate parsing to MinIntegrity::from_policy_str, keeping default behaviors intact.
• Added unit tests covering MinIntegrity::from_policy_str parsing behavior and extract_repo_from_item’s primary lookup strategies and precedence.

Show a summary per file

File	Description
guards/github-guard/rust-guard/src/labels/helpers.rs	Centralizes integrity parsing in MinIntegrity::from_policy_str, updates rank/label helpers to use it, and adds unit tests for integrity parsing + repo extraction.

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• Files reviewed: 1/1 changed files
• Comments generated: 0

[lpcox]

@copilot fix failing ci check https://github.com/github/gh-aw-mcpg/actions/runs/27367774755/job/80873393067?pr=7386

[Copilot]

@copilot fix failing ci check https://github.com/github/gh-aw-mcpg/actions/runs/27367774755/job/80873393067?pr=7386

Fixed in 7a0c1ef. The main branch already had extract_repo_from_item tests, so my commit introduced duplicate function names. I've removed the duplicate block — the MinIntegrity::from_policy_str tests are retained and all 471 tests pass.