Task: Carry a run's input through object storage

A run's input of any size imports, and the workflow request carries a storage key rather than the files.

• ore import-run uploads the input directory to the platform bucket and sends its key; the import step downloads it.
• The Products example imports.
• The inline size check in the shell is removed.

(Implementation strategy. Written when work starts; key decisions are distilled into the parent story's * Decisions at close, but the plan itself stays — it is the historical record of what we did.)

Every number this task claims about a tree, with the command that produced it and the commit it was measured at. A number without both is not a measurement, because a clean-up record describes a tree and trunk moves under a branch: a consumer count, a gate's component count and a suite's size all change with no code changing, and the reader of a bare number cannot tell which tree it came from. Where the raw output matters, put it in an evidence/ file beside the task and name that file in the Command column.

Raised in the review of PR #2647: the input travels inline, NATS refuses a message over its 1 MB limit, and the Products example's curve configuration alone is over 500 KB. The shell refuses an input over 900 KB with the reason until this lands. The workflow request also carries the files, which this removes.

Manual QA scenarios (scaffolded via compass add test_scenario) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.