Refresh the usage bars every 5 minutes, not every hour

The 5h/7d bars were served from a cache with a one-hour TTL, so a bar
could sit unchanged for most of a 5-hour window. The TTL is now a named
config setting next to GIT_CACHE_SECS at 300s: worst case 12 requests an
hour, shared across every session through /tmp/claude.

The section header claimed "cached 60s" — inherited from upstream and
never true here — which is what set the expectation the code did not
meet. It now names the setting instead of a number that can drift.

The refresh is gated on the same width-tier check as the bars, so a
render that shows them is a render that refreshes them: the new tests
pin that from full width down to WRAP_FLOOR, and pin that one column
below it, where the bars are dropped, no request is paid for either.
Those widths are given in usable columns, as in the sibling width test,
so the suite does not depend on the padding in the live settings.json.

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

claude/tests/run.sh

@@ -11,7 +11,8 @@ cd "$(dirname "${BASH_SOURCE[0]}")" || exit 1
 
 status=0
 for t in statusline.isaacaudet.payload_test.sh \
-         statusline.isaacaudet.width_test.sh; do
+         statusline.isaacaudet.width_test.sh \
+         statusline.isaacaudet.cache_test.sh; do
     echo "== $t"
     bash "$t" || status=1
     echo