Update policies documentation for clarity and accuracy

[octo-ryanhall]

• Revised the overview of policies to emphasize automatic enforcement of deployment standards.
• Clarified the input schema for policies, detailing available fields and their usage.
• Enhanced troubleshooting section to provide clearer guidance on diagnosing common policy evaluation issues.
• Updated examples and best practices for writing effective Rego conditions in policies.
• Adjusted publication and activation instructions for policies to ensure proper usage.

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