docs: mark learn v3 as shipped

Record what landed against each item in the plan, where it lives, and the one
item that did not: F6 (learn to runtime policy). The emitter is trivial but
nothing in the wrap or the hooks reads a policy file, so shipping it alone would
be scaffolding for a reader that does not exist. It needs a decision about where
enforcement lives first.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>