[Devin-Holland]

Follow-up to #1975 from feedback on stage.

⊙ Problem

The Admin → Hosts columns ran together: Studio's table cells have no padding. "1" instances and "0.1 / 4" CPU read as "10.1 / 4". A shared host's Organizations cell listed every organization with an instance on it. The location repeated a full place name. CPU showed a decimal nobody could interpret.

🤔 Should the per-instance organizations leave the table entirely?

No, they move to the panel. Staff still need "who runs on this shared host", just not in a column that grows with every tenant.

💡 Solution

• Cells are padded, and a host's id shows only when it differs from its name.
• Organizations lists only the organizations a host is dedicated to, or "Shared".
• Clicking a row opens a details panel with everything else, including the organizations with instances on the host and their counts. Closing it returns focus to the row's host name.
• Location shows us-east1-b · gcp.
• CPU shows the share of cores busy, e.g. "3% of 4 cores".

🤔 Why a percentage for CPU?

usedCPUCores is not an allocation. Each heartbeat, the host manager samples CPU for 100 ms and reports busy cores, so "0.1 of 4" meant 0.1 cores busy at that instant. A percentage says that without implying fractional reservations.

⚖️ Alternatives

• Expandable rows instead of a panel: a shared host's organization list is long enough to push the rest of the table off screen.

🔧 Changes

• src/features/admin/hosts/index.tsx: the table changes, the details panel, and the CPU and usage formatting. Central-manager stores -1 when a host leaves a usage value out; that now shows as unknown instead of "-1". The panel holds the clicked host, so a refetch that drops it neither closes nor later reopens it, and keeps its content while it slides closed.

✅ Verification

• pnpm test 5947 passing on this head. Page tests and formatter tests cover:

  • the dedicated-only Organizations column, the short location, and the id shown only when it differs;
  • the panel opening from a row and from the host name, staying on its host while a filter change drops it, and returning focus on close;
  • the CPU percentage and the -1 and zero-capacity formatting.

  Reverting any of these fails a test.

• Rendered the real page against stub data shaped like stage's four hosts (desktop dark, and mobile): columns separate, the panel lists the per-instance organizations with counts.

Related PRs: #1975 overlaps (this follows it up; it is merged)
Complexity: low

_{🤖 Generated by Claude Code (Claude Opus 5.5); posted via @Devin-Holland.}

_{Review-Coverage: authored=claude; ran=codex,gemini; adjudicated=domain; blocked=cursor-composer(auth); declined=cursor-grok,cursor-kimi,cursor-muse,muse; rounds=1; full=1 @ 23cddf6}

_{Review-Attention: read ~6m (decisions: whole-row-click-opens-modal, org-column-dedicated-only, location-code-over-name, cpu-as-sampled-percentage, do-less-alternative; raised: degraded review) @ 23cddf6}

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	80.33%	15248 / 18980
🔵	Statements	80.27%	16191 / 20169
🔵	Functions	75.77%	4107 / 5420
🔵	Branches	74.88%	11887 / 15873

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/features/admin/hosts/index.tsx	89.55%	79.74%	84%	92.52%	137, 138, 139, 303-304, 308, 313-315, 327, 365-377

Generated in workflow #2412 for commit 23cddf6 by the Vitest Coverage Report Action