docs: clarify deferred mailbox lifecycle
docs: the two mechanisms that guarantee a reasoning tree can produce a signal Companion to the checkable-object tooth. Documents the refutation pairing (a for-all goal is seeded with one node a machine can decide, exploiting the asymmetry that confirming needs an argument while refuting needs one witness) and the per-node acceptance criterion (schema v38), including why the latter counts the absence rather than rejecting it — a construction node is legitimately task-shaped, a deliberate session's nodes are questions, and some subgoals are settled only by argument.
docs: the verification tooth that is not mode-scoped Deep-Reasoning presented the teeth as formal-mode furniture, which is exactly the hole the Jacobian session fell into: mode is picked once at entry, so a formal object arriving inside a deliberate session met nothing. Documents the tooth now standing there, and the three properties that let it default on — refuse-once, stand down as soon as the session computes anything, and never tell the model what to conclude ("if the object turns out to be wrong, that is the finding").
Align with README restructure: plan-gate compute exemption (EN+ZH) + three-tier routing section
Add bilingual developer wiki (12 topics + Home + nav)