feat(design): every version keeps its full simulation, and own hypotheses stop wiping ours

Writing your own hypothesis deleted the generated ones. `applyOwnHypothesis`
built `[own]` and replaced the list outright, so the one moment a researcher is
best placed to write a sharp hypothesis - having just read four of ours - was
the moment acting on it destroyed what they had read. Theirs is now added on
top and selected, the rest stay. There is also an inline "write your own" block
under the generated list, so it no longer means leaving the page for a tab.

Version outcomes were a sentence. The elaborate simulation result - the
distribution, run count, guardrails, gotchas, gap analysis, proposed changes -
only ever existed for whichever simulation was most recent; once a version was
superseded all that survived was a one-line verdict. The whole simulation is
now stored on the version, and one shared component renders every occurrence:
verdict always visible, full working behind an expander. Auto mode was worse
than that - its snapshots recorded no outcome at all, so an unattended run left
a stack of versions with no record of why any was superseded. It records the
same as the manual path now.

Reopening Validate for a new version showed the OLD version's results. The
stored simulation described the design that had just been replaced, so the
previous verdict and its full working framed the simulate button for the new
one, with nothing saying which was which. It is cleared on regeneration; the
old result lives on its version snapshot, which is what "Earlier rounds" reads.

Also: designs are labelled Auto mode vs Built by you on the design page, the
dashboard and the project canvas - the two were indistinguishable though they
warrant different scrutiny; the auto loop shows the same regeneration progress
as the manual path instead of sitting on the superseded protocol; and the
Export rail and template picker hold a placeholder during their first fetch
rather than asserting emptiness and then contradicting it a second later.

Two pre-existing test failures (clarify.test.ts, pipeline.test.ts) are
unrelated and fail identically on earlier commits.

Author: piyushmahajan7749