* feat: add dialog for "Start new session from this answer"
Replace the one-click fork action on assistant messages with a dialog
(ForkSessionDialog) that lets the user pick model, thinking level, and
agent, plus edit the instructions sent to the new session.
The instructions field is prefilled with the previous fixed fork prompt
and is mandatory. The composed message is now fully visible (no synthetic
preface): the user's instructions sit above a short fixed connective that
opens the assistant content. createSessionFromAssistantMessage takes the
chosen execution params instead of reading from config.
Also fix TodoSendDialog visuals: narrower vertical layout, model trigger
no longer stretches with centered text, and the agent/thinking dropdowns
portal to body so opening them no longer nudges the dialog height. Extract
the shared ThinkingPill into its own component.
* fix: address review feedback on fork session dialog
- Fix "bellow" -> "below" typo in the fork content preface (now user-visible
since the message is no longer synthetic)
- Reset ForkSessionDialog state only on open transition, reading the config
store snapshot via getState() so background store refreshes can't discard
in-progress instruction edits
Bohdan Triapitsyn
6a88cd09cc