CI: Hypatia crashes on main — 'did not produce one valid findings array' (exit 2) #108

Problem

Hypatia Security Scan / hypatia / Hypatia Neurosymbolic Analysis fails on main (fc12a2e) and on PRs. The failure is a crash of the tool, not a finding:

##[error]Hypatia did not produce one valid findings array
##[error]Process completed with exit code 2.

A scanner that emits no findings array reports nothing about the tree. The red is therefore also not evidence that anything was found. Separately, Mirror to Git Forges (bitbucket, codeberg, disroot, gitea) is red on main.

Acceptance criteria

• On main, Hypatia emits exactly one valid findings array. The job then concludes on the findings: green if the array is empty, or a red that names the findings.
• The fixing PR names why the array was missing or malformed. Candidate causes are a crash, empty stdout, several arrays concatenated, or a non-JSON preamble.
• Mirror jobs are green on main, or are disabled for forges that are deliberately not mirrored, with a stated reason.

Found while landing #107. #107 inherits this red and does not cause it: job 109943475111 fails the same way.