T1: Cache-Control max-age=60 on /topics/, /repos/, /domains/ list endpoints
so repeated dashboard polls within a minute are served from browser cache.
T2: ETag middleware (md5 hash) on all JSON GET responses with conditional-GET
(304 Not Modified) support; If-None-Match and ETag added to CORS headers.
ETag registered inside CORS so 304s automatically carry CORS headers.
T3: GET /state/deps — lightweight dep-graph endpoint returning open workstreams
with depends_on/blocks edges only, skipping the 10-table full-summary query.
Prerequisite for T4 (switching workstreams.md and dependencies.md off /state/summary).
Workplan: CUST-WP-0039-dashboard-poll-optimization.md
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
tegwick
b832032cc3