Potential fix for code scanning alert no. 1: Workflow does not contain permissions

[jonathanmagambo]

Potential fix for https://github.com/jonathanmagambo/Polykit/security/code-scanning/1

To fix the problem, explicitly define a permissions block that grants only the minimal required scopes for this workflow. Since the job only checks out code and runs cargo build/cargo test, it needs at most read access to repository contents and does not require write access to anything.

The best minimal fix without changing functionality is to add a top-level permissions block (applies to all jobs) just after the on: section. Set contents: read, which is sufficient for actions/checkout@v4 to function. No other scopes (like pull-requests, issues, etc.) are needed based on the shown steps.

Concretely, in .github/workflows/rust.yml, insert:

permissions:
  contents: read

between the on: block (lines 3–7) and the env: block (line 9). No imports or additional definitions are required, as this is pure YAML configuration.

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