[VRP] Untrusted fuzzer UI

[PauloVLB]

Problem

We need a way to identify fuzzers that are "untrusted" (e.g., external fuzzers provided by VRP researchers) so we can apply different security policies to them (like restricting where they can run). Currently, there is no field in the UI or Datastore to manage this state.

Proposed Solution

We added a trusted boolean field to the Fuzzer model in Datastore (defaulting to False for safety) and exposed it as a "Trusted" checkbox in the Fuzzer management UI. This ensures all new fuzzers are treated as untrusted by default, maximizing security.

Key changes:

• Added trusted boolean property to Fuzzer model (default False).
• Factored out job validation logic into a centralized helper check_job_supports_untrusted_workloads in data_handler.py for consistent enforcement between fuzzers and testcases.
• Added a migration script to set trusted=True for existing fuzzers to maintain backward compatibility.

UI Change

Trying to run an untrusted fuzzer (i.e. trusted is unchecked) on a non-Linux job gives a clear error:

Testing

Validated by deploying to dev and verifying that the checkbox state is correctly persisted to and loaded from Datastore. Added/updated unit tests to cover the trusted property and validation helper.

Validation

I have uploaded a fuzzer with trusted set to false; here is a screenshot.

[letitz]

Thanks for sending this! Overall I think we should invert the trusted/untrusted bit to make trust explicit instead of implicit, and default to safety in the absence of an explicit trust signal.

[PauloVLB]

I have updated the PR description to reflect the changes requested by @letitz and added the migrate_fuzzer_trusted.py migration to set all existing fuzzers as trusted.

[letitz]

LGTM % responding to comments below and to avoid blocking on me further as I go OOO.