ci(ai-validation): fail-fast on traversal paths (consistency w/ non-regular guard)

Copilot finding on PR #1959 (line 114): the path-traversal hardening
block used `continue` (skip-with-warning) on detection of absolute /
traversal paths, but the non-regular-tree-entry check below uses
`exit 1`. The asymmetry meant a fork PR that smuggles in a path like
`docs/../../outside.md` would silently bypass Pass 1 (no file copied
into _changed_md/) and Pass 2 (LLM Read/Glob/Grep tools see no
content) — reducing validation coverage on exactly the inputs that
warrant the closest look.

Change `continue` to `exit 1` so both unsafe-input checks have
consistent visible-failure semantics. Maintainers must explicitly
address an offending path rather than have it skipped.

Mirrored byte-identically across all three open workflow PRs.

0 files changed, 0 insertions, 0 deletions