Make the Session outline compact and decision-first

Traceability

• Spec ID: compact-session-outline
• Status: Implemented

Intent

Reduce the Session outline by removing low-value items inside its sections, not by removing the sections themselves. Keep Cell navigation, the complete historical Evidence filters, a small set of identifying Session facts, and then the Usage and context decision. Preserve the original Evidence filters disclosure interaction and contents; its collapsed default already prevents the checkbox list from consuming initial height. Keep the standalone Inspector and React Studio surfaces aligned.

Acceptance Scenarios

• AC-1: Read-only and bulk Expand/Collapse are absent. The outline retains its pane title, Cell jump control, Evidence filters section, Session facts section, and Usage and context in that order.
• AC-2: Evidence filters preserves its original disclosure interaction: it is collapsed by default, opens from its summary by pointer or keyboard, and uses the existing bounded popover treatment at compact/narrow widths. Its expanded content restores Prompts, Results, Intermediate, Model usage, Commits, Tool calls, retained tool-name subtypes, and File paths with their historical counts. The original total-call count remains visible in the disclosure summary at wide layout.
• AC-3: Session facts is directly visible and contains exactly Runtime, Model, and Duration. It contains no Source, Turns, Tool calls, File edits, or Projection rows.
• AC-4: Every restored evidence and tool-name filter works independently, and each Process disclosure remains independently operable.
• AC-5: The default Usage and context summary begins within 230 px of the outline's top edge at wide layout, with no horizontal overflow.
• AC-6: Compact and narrow layouts preserve visible focus, reachable controls, and the existing 44 px narrow touch targets without document overflow.
• AC-7: Standalone Inspector and React Studio render the same outline hierarchy and behavior.

Non-goals

• Changing retained Session evidence, Usage calculations, Replay, or the Session notebook stream.
• Restoring bulk Process controls or duplicated facts in another disclosure, menu, or pane.
• Redesigning the full Usage report.

Plan and Tasks

1. Remove read-only status and bulk Process actions; retain one full-width Cell jump control.
2. Update the shared Inspector stylesheet for wide, compact, and narrow modes.
3. Restore the full historical filter disclosure and render three high-value Session facts in a compact always-visible row; remove only low-value facts.
4. Preserve corresponding React/standalone filter state and handlers.
5. Assert the restored Evidence filters disclosure, exact retained items, filter behavior, and decision position.

Test and Review Evidence

• AC-1/AC-2/AC-3/AC-7: the focused Studio browser scenario confirmed the compact outline hierarchy, the original disclosure interaction, all 10 fixture filters and counts, and standalone/Studio parity.
• AC-4: the focused Studio browser scenario confirmed independent Model usage, tool-name, Tool calls, Prompts, and File paths behavior. The regenerated standalone report also confirmed independent Model usage and Tool calls.
• AC-5/AC-6: the Studio browser scenario passed at 1440x900, 1024x768, and 390x844 with the Usage offset within 230 px, no document/pane overflow, and 44 px narrow filter/select targets. Its narrow disclosure popover remained within the viewport. Collapsed wide/compact/narrow and expanded narrow screenshots were visually reviewed.
• npx vitest run test/reporting/harness-inspector.test.mjs: 39 passed.
• Studio typecheck and build passed; the full Studio suite passed 512 tests; the focused Studio Inspector browser scenario passed.
• Standalone report regeneration succeeded. The full visual-contract run passed its first three wide surfaces, then stopped before Session Trace because concurrent activity-chart work requires a long idle scale-break fixture that this real report does not contain; no Session-outline failure was reported.
• Preview /health returned ok, /canvas-module.js loaded, and git diff --check passed.
• Risk: the restored filter list can be tall when expanded. It remains collapsed by default, and the compact/narrow popover is bounded and scrollable instead of increasing the initial outline height.