Fix Overview layout: stats panel, filter panel, then tables (in that order)

Placing the filter form outside the polled div (so the poll can't wipe out
typed/selected values) put it before the stat-grid, since both used to
live inside that same polled block — stats ended up after the filter
instead of before it, as it always was.

Splits the stat-grid out into its own #overview-stats div, positioned
before the filter form; the actual poll target is now #overview-tables
(just the two tables). Since #overview-stats no longer polls directly,
/overview/fragment now also renders it as an out-of-band swap alongside
the main #overview-tables response — the same hx-swap-oob idiom already
used for the shared error banner — so the stat counts still refresh every
tick even though they're outside the polled element.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

bin/SHA256SUMS

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