test(ui): app.runs.tsx's pure mapping helpers and SavedViews flow have zero direct test coverage

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⚠️ Definition of Done: this issue must be completed in full, in a single PR. Do not split this
work across multiple PRs, and do not defer any Deliverable below to a follow-up issue. A PR that
satisfies only some of the Deliverables, stubs a required test, or leaves a checkbox
partially-done does NOT resolve this issue and will be closed.

Context

apps/loopover-ui/src/routes/app.runs.test.tsx only covers the drawer's copy buttons and the
filter-bar reset control (confirmed by grep:
grep -in "SavedView|groupByDate|mapAgentRunBundle|mapSignalFidelity|mapAgentRunKind" returns
nothing). The following pure mapping helpers have zero direct test coverage:

• mapSignalFidelity (app.runs.tsx:516-523) — 4 branches (complete → ready, degraded →
  degraded, blocked → blocked, default → stale), none exercised.
• mapAgentRunKind (:509-514) — 4 branches, none exercised.
• mapAgentRunBundle (:458-507) — including the repo-fallback chain
  (targetRepoFullName ?? payload.repoFullName ?? input?.repoFullName ?? "unknown") and the
  counterfactuals-pooling/snapshot-replay construction, none exercised.
• SavedViews' save/apply/remove flow (:572-670), untested.

Requirements

• Add direct unit test coverage for mapSignalFidelity, mapAgentRunKind, and mapAgentRunBundle
  (all branches), plus a render-level test for SavedViews' save/apply/remove flow.

Deliverables

• mapSignalFidelity is tested for all 4 branches, including the default/fallthrough case.
• mapAgentRunKind is tested for all 4 branches.
• mapAgentRunBundle is tested exercising each level of the repo-fallback chain
  (targetRepoFullName present, absent-falls-to-payload.repoFullName,
  absent-falls-to-input?.repoFullName, all absent-falls-to-"unknown").
• SavedViews has a render test: save a view, confirm it appears in the list, apply it, remove
  it.

All four Deliverables are required in the same PR.

Test Coverage Requirements

apps/** is excluded from codecov/patch gating, but apps/loopover-ui's own local vitest
coverage thresholds apply — every branch listed above currently has zero coverage.

Expected Outcome

The pure mapping helpers and saved-views flow that app.runs.tsx depends on — currently entirely
untested — have direct, explicit branch coverage, protecting them from a silent future regression.

Links & Resources

• apps/loopover-ui/src/routes/app.runs.tsx:458-523,572-670
• apps/loopover-ui/src/routes/app.runs.test.tsx (existing test file to extend)

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JSO-6043