Improve agents UI timeline and runtime client safety

[samwillis]

Summary

• Refines the agents server UI timeline, sidebar, workspace chrome, and context inspection flows with richer manifest/status rendering and split/tile ergonomics.
• Adds a general-purpose low-cost model runner path for agents tooling and updates Horton/extract-meta to use it.
• Tightens agents UI TanStack DB live queries and adds a browser-safe @electric-ax/agents-runtime/client export so the UI avoids server-only runtime modules.

Test plan

• pnpm -C packages/agents-runtime build
• pnpm -C packages/agents-server-ui typecheck
• pnpm -C packages/agents-server-ui build

Made with Cursor

[codecov]

Codecov Report

❌ Patch coverage is 6.07357% with 1098 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.22%. Comparing base (744c47f) to head (8dc6d2a).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...agents-server-ui/src/components/EntityTimeline.tsx	0.00%	268 Missing ⚠️
...s-server-ui/src/components/EntityContextDrawer.tsx	0.00%	150 Missing ⚠️
packages/agents-runtime/src/model-runner.ts	6.76%	124 Missing ⚠️
...ckages/agents-server-ui/src/components/Sidebar.tsx	0.00%	62 Missing ⚠️
.../agents-server-ui/src/lib/workspace/dragPayload.ts	0.00%	50 Missing ⚠️
...nts-server-ui/src/components/JsonInspectDialog.tsx	0.00%	47 Missing ⚠️
packages/agents-runtime/src/tools/fetch-url.ts	30.30%	46 Missing ⚠️
...nts-server-ui/src/hooks/useWorkspacePersistence.ts	0.00%	36 Missing ⚠️
...rc/components/stateExplorer/StateExplorerPanel.tsx	0.00%	34 Missing ⚠️
packages/agents-server-ui/src/lib/sendMessage.ts	0.00%	31 Missing ⚠️
... and 35 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4288      +/-   ##
==========================================
+ Coverage   55.48%   57.22%   +1.74%     
==========================================
  Files         193      227      +34     
  Lines       19599    23013    +3414     
  Branches     5065     6002     +937     
==========================================
+ Hits        10874    13170    +2296     
- Misses       8721     9838    +1117     
- Partials        4        5       +1     

Flag	Coverage Δ
packages/agents	60.31% <28.57%> (+1.37%)	⬆️
packages/agents-runtime	79.18% <22.27%> (-1.04%)	⬇️
packages/agents-server	69.16% <ø> (ø)
packages/agents-server-ui	5.40% <1.95%> (-0.65%)	⬇️
packages/electric-ax	38.04% <0.00%> (-0.55%)	⬇️
packages/experimental	87.73% <ø> (?)
packages/react-hooks	86.48% <ø> (?)
packages/start	82.83% <ø> (?)
packages/typescript-client	94.32% <ø> (?)
packages/y-electric	56.05% <ø> (?)
typescript	57.22% <6.07%> (+1.74%)	⬆️
unit-tests	57.22% <6.07%> (+1.74%)	⬆️

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