Security: TLS Certificate Integrity Fix

[MichaelSovereign]

Summary

This PR hardens the TLS configuration module by adding security checks for pinned certificate file permissions.

Changes

1. Permission Validation: Updated to check the file system permissions of the pinned certificate (). If the file is writable by anyone other than the owner, the module will now log a security warning and fallback to the system CA bundle. This prevents a local attacker from replacing the pinned certificate to perform Man-in-the-Middle (MitM) attacks.
2. Defensive Fallback: Ensures that insecure configuration states fail-safe by defaulting to the more trusted system root CAs.

Closes #6460

[Scottcjn]

Closing as part of Tier 0 hard-ban cleanup — see #3074 / #3104 / #3169 for the documented incident chain. All MichaelSovereign PRs are closed unread per the Tier 0 contract. No review path; no future PRs from this account will be processed. (See feedback_michaelsovereign_tier0_2026-05-02.md.)