The whole comparison — locations, comfort target, band, judged temperature
and date range — is now encoded in the URL hash (c/t/b/s/e/loc) and read
back on load, so a link reproduces exactly what's on screen. Comfort, band
and judged-temperature edits still re-rank instantly and update the hash
without a fetch.
Editing the date range or the location set no longer refetches on its own:
it marks the comparison dirty and reveals a single "Refresh comparison"
button next to Add location; the load runs only when it's tapped. Pending
locations show a dashed chip until then. The initial view (from a shared
link, the saved set, or the last-viewed spot) still loads on arrival.
Compare page (frontend/compare.{html,js} + /thermograph/compare route):
line up several places over a date range and rank which best matches a
comfort temperature. Per location it pulls the same daily record the
Calendar uses and, per day, takes a chosen temperature (daytime high /
daily mean / overnight low / feels-like) against the comfort target. A
day "hits comfort" when it lands within an adjustable band; otherwise it
counts as colder or warmer and the average miss is tracked. Results are
ranked by comfort-day share (tie-broken by the smaller typical miss),
with a diverging below/comfort/above bar and per-bucket stats. Comfort,
band and judged temperature re-rank instantly client-side; only the
location set or date range trigger a data load (shared calendar cache).
Feels calendar filter: drop the comfort-temperature slider and the
client-side felt-high/felt-low re-pick. The Feels metric now colors by
the server's combined feels-like value like the other metrics, so its
tab matches the rest of the metric selector.
