Home's Server-Timing names its regions: feed, KPI row, pinned panels, shelf #3181

/ now names its regions in Server-Timing, with desc="hit" on a phase whose cache answered. The new test and the existing home, route-timing and map-cache tests pass. I couldn't run the type check here (bun x tsc can't write to its temp dir and the bun types are missing), so the forge's check will be its first run.

• Phases: a signed-in home records feed, kpis and panels. The anonymous door records shelf.
• No phase for a hidden region: kpis and panels are recorded only where the page renders them (admin, not the lean first-steps view). A non-admin gets feed alone, and an anonymous visitor gets shelf alone.
• Hit marking: src/core/route_timing.ts gains timePhase and timePhaseAsync. They mark a phase as a hit when the cache's hit count rose and its miss count didn't. Under concurrent requests a hit can be credited to the neighbouring request.
• feed scope: it times the whole region (ranking and rendering), with the candidate cache inside it.
• Test: test/home-timing.test.ts checks the three viewers and that a warm owner's kpis and feed carry desc="hit". It also checks the header format for a hit and a miss.
• Docs: docs/CACHING.md has a "Where home's time goes" section with one run from the new bench/home-phases.ts. The owner's p50 and p95 are app 15.3 and 19.7 ms, feed 7.1 and 10.0, kpis 0.2 and 0.3, panels 0.1 and 0.1.

Left out: the issue didn't ask for a session phase on /, so I didn't add one. The shelf phase wraps the front-page read and building the tiles, not the final render.

Try it: bun test test/home-timing.test.ts, or bun run bench/home-phases.ts to print the table. Or load / and read the Server-Timing response header.

Closes #3160

/ now names its regions in Server-Timing, with desc="hit" on a phase whose cache answered. The new test and the existing home, route-timing and map-cache tests pass. I couldn't run the type check here (bun x tsc can't write to its temp dir and the bun types are missing), so the forge's check will be its first run.

• Phases: a signed-in home records feed, kpis and panels. The anonymous door records shelf.
• No phase for a hidden region: kpis and panels are recorded only where the page renders them (admin, not the lean first-steps view). A non-admin gets feed alone, and an anonymous visitor gets shelf alone.
• Hit marking: src/core/route_timing.ts gains timePhase and timePhaseAsync. They mark a phase as a hit when the cache's hit count rose and its miss count didn't. Under concurrent requests a hit can be credited to the neighbouring request.
• feed scope: it times the whole region (ranking and rendering), with the candidate cache inside it.
• Test: test/home-timing.test.ts checks the three viewers and that a warm owner's kpis and feed carry desc="hit". It also checks the header format for a hit and a miss.
• Docs: docs/CACHING.md has a "Where home's time goes" section with one run from the new bench/home-phases.ts. The owner's p50 and p95 are app 15.3 and 19.7 ms, feed 7.1 and 10.0, kpis 0.2 and 0.3, panels 0.1 and 0.1.

Left out: the issue didn't ask for a session phase on /, so I didn't add one. The shelf phase wraps the front-page read and building the tiles, not the final render.

Try it: bun test test/home-timing.test.ts, or bun run bench/home-phases.ts to print the table. Or load / and read the Server-Timing response header.