Add pop-out button to open a section in its own tab (ticket 036)

Each of the four primary sections (Log viewer, Params, Metrics,
Dashboards) gets a PopOutButton next to its CollapseToggle/HelpIcon that
opens `?section=<id>` in a new tab via window.open. App.tsx branches on
that query param to render just the one section full-page, with no
NavMenu/FilterBar/sibling chrome — Metrics/Dashboards get the range that
was active at pop-out time via startMs/endMs query params (they have no
LogTimeline of their own to pick one), Params gets a small self-contained
params fetch since it has no LogPreview sibling to share state with, and
the popped-out Log viewer owns its own copy of the log/timeline polling
state.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

tickets/036-section-open-in-new-tab.md

@@ -1,42 +0,0 @@
-# 036 — Open a section in its own tab
-
-## Summary
-
-`App.tsx` has no routing at all — `NavMenu`, `FilterBar`, `LogTimeline` +
-`LogPreview`, Params ([034](034-params-declaration-ui.md)), `Metrics`, and
-`Dashboards` all render together in one fixed layout
-(`webapp/src/App.tsx:94-108`). Add a small icon next to each section's
-collapse toggle ([035](035-collapsible-sections.md)) that opens *just that
-section* in a new browser tab — no `NavMenu`, no other sections — for
-pop-out/multi-monitor use.
-
-## Scope
-
-- A "pop out" icon button in each of the four section headers (Log viewer,
-  Params, Metrics, Dashboards), alongside the collapse toggle and "?" help
-  icon.
-- Clicking it opens a new tab (`window.open`, not same-tab navigation) at a
-  URL identifying that section, e.g. `?section=metrics`.
-- Minimal client-side routing in `App.tsx`/`main.tsx`: when a `section`
-  query param is present, render only that one section full-page — no
-  `NavMenu`, no `FilterBar` unless the Log viewer section needs it, no
-  sibling sections.
-- The standalone view keeps the section's own functionality intact (e.g. the
-  popped-out Metrics tab can still declare metrics; popped-out Dashboards
-  can still edit/autosave panels) — it's a layout change, not a read-only
-  view.
-- The popped-out tab reflects the current `range` state (time range) at the
-  moment it's opened, passed via query params, since it has no `LogTimeline`
-  of its own to select one (unless the Log viewer section itself is what's
-  popped out).
-
-## Acceptance criteria
-
-- Clicking a section's pop-out icon opens a new tab showing only that
-  section, with no nav bar and no other sections.
-- The popped-out section is fully functional (not a static snapshot).
-- Closing the popped-out tab has no effect on the original tab's state.
-
-## Depends on
-
-- [035 — Collapsible primary UI sections](035-collapsible-sections.md)