(cherry picked from commit 1db02545f74c96b3b92be4fc32954659cec1f814)
Reconcile-conflict: A14b E402 imports referencing cloud.handler_core (does not exist here; core methods live in server.py) — kept HEAD imports with incoming's noqa: E402 markers, dropped the unused core_mod import (verified unused elsewhere in both files).
Only pure computation/validation sub-blocks of _handle_github_webhook,
_create_followup, _deliver_to_thread and _task_chat_history are extracted;
all DB writes, audits, external calls and side-effect blocks stay in the
callers, error strings/codes and response shapes verbatim. _deliver_to_thread
uses the shared goal classifier only for /goal input: its non-goal terminal
path still goes to CAS revive (not 409) and its merged path keeps its own
wording. New tests: test_longfunc_remaining.py (15).
host