Sharing (tag/assign/reallocate) is now a collapsed-by-default section in
the task drawer with a one-line summary, since it's a lesser-used function
that was eating space on every task.
list_id is now optional on task creation -- the task lands unfiled (same
state assign/reallocate already use), scoped only by project_id. Projects
are a cross-cutting grouping, not a list replacement, and the only way to
add a task to a project was previously to create it elsewhere and set the
Project field from the drawer. Added a "+ New task" input directly on
ProjectDetailView. Verified against a throwaway Postgres: unfiled creation,
distinct sort_order per unfiled task, project detail lists them, and
existing validation (bad list_id, missing title) still rejects.