Projects become schedulable planning objects alongside their issues: add
optional start_date / due_date, mirroring issue.start_date / issue.due_date.
This is only the first slice of #5227 — labels, metadata, and the editable
metadata UI are still out of scope.
- migration 166: two nullable DATE columns on `project` (calendar days, no
FK/index — matches the issue end-state after migration 112)
- sqlc CreateProject / UpdateProject carry the dates; UpdateProject uses
narg so an explicit null clears
- handler: parse YYYY-MM-DD (400 on bad format), rawFields-presence clear on
update, and the hand-scanned SearchProjects query returns the columns
- CLI: `project create/update --start-date/--due-date` (empty clears on update)
- frontend + mobile types/zod schemas: the two new schema fields are
nullable().default(null) so a project from an older backend (frontend
deploys before backend) parses to null instead of degrading the batch to
the empty fallback; added a search schema drift test
- projects skill / CLI docs
Part of #5227
Co-authored-by: J <j@multica.ai>
Co-authored-by: multica-agent <github@multica.ai>
