* fix(agent-session): refuse a pre-commit structured create with an envelope
The create route refused by throwing, which reaches a client as a generic
transport error indistinguishable from a lost answer — so desktop parked the
launch as visibility-unknown with no chat and no terminal. Convert the whole
pre-commit span, everything before `attach`, into a refusal envelope carrying a
code, and name the definitive-refusal allowlist the fallback decision needs.
* fix(agent-session): gate legacy fallback on definitive refusals
* fix(mobile): preserve unknown structured create outcomes
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Co-authored-by: Merge Sim <sim@local>
Brennan BensonandMerge Sim
cc07249e78