Addresses final code review:
- to_int/1 now returns 0 on nil or unparseable strings instead of crashing
- remove unused .pool-row CSS (superseded by .pool-block)
- clamp capacity bar width to [0, 100] to prevent visual overflow
- pool_scrub_line/1 uses scan_function so resilver shows as "resilver..."
Addresses code review: differentiate pool_scrub_line/1 FINISHED clause
with the word "finished", test the degraded-vdev callout via a second
DEGRADED pool in the fixture, and replace the generic "scrub" match
with an assertion on the full finished line.
Returns 200 with {status: ok, version, db: ok} when SQLite is reachable,
503 when the DB probe fails. Unauthenticated so external monitors can
poll without credentials.
