Add /api/library datasheet import and component GET/PUT with no exam.
Reorganize pytest into datasheet, library, schematic, PCB, and AF+AI.
Document Rust criteria (none chosen; no rustup) and coding conformity.
The status watcher synthesized pcb_error with pcb_status=complete (terminal)
when the worker finished before pcb_complete arrived. Map that hatch to
pcb_complete, publish the event before flipping status, and send /pcb to
the layout report tree.
michele