The startup probe validated only the mapping flags against the trivial
program `true`, but the real launcher always adds
--mount --ipc --pid --uts --fork. On environments where the user
namespace is created but mount propagation inside it is restricted
(e.g. AppArmor-restricted CI runners), the fallback mapping passed the
probe and the sandbox activated, yet every sandboxed command died with
"cannot change root filesystem propagation: Permission denied",
silently returning empty tool output and breaking the mock parity
suite.
The candidates now define the complete static launcher shape (mapping
flags + namespace flags), so probe success implies launch success; the
launcher reuses the candidate instead of re-appending the namespace
flags, keeping probe and launch as one source of truth. The
order-guarding test asserts the namespace flags are present in every
candidate.
Co-authored-by: linkst <2024023709@m.scnu.edu.cn>
