Optimize transcript no-filter search path - #1723

Canonical issue

Linked automatically.

Outcome

Transcript filtering now avoids allocation when no search or speaker filter is active, while preserving null/empty-query behavior and one-time query normalization.

if (!search && !speaker) return segments as TranscriptSegment[];

Scope

• Included:
  • No-filter fast path in filterSegments
  • Regression coverage for preserving original segment identity
• Explicitly excluded:
  • UI changes
  • Workflow/provenance gate changes
  • Unrelated billing/type-check fixes

Risk

• Risk level: low
• Failure mode: filtered transcript list could skip allocation but return stale references only when callers mutate segment arrays unexpectedly
• Rollback: remove the early return and the matching identity assertion

Verification

Current head: 56c6c06707c41e9e50d39150f09c782cb60e4008

• Focused tests: npm test --workspace apps/web -- src/lib/__tests__/transcript-search.test.ts
• Required CI
• Review threads resolved

Production evidence

Not applicable yet; this is a pure transcript-filter helper change. Preview/runtime evidence should attach to the current head if repository governance requires web deployment proof.

Agent handoff

• One canonical issue is linked
• No competing PR implements the same issue
• Acceptance criteria are satisfied
• Required checks pass on the current head
• Human decision is requested only for product, security, irreversible infrastructure, or production approval

• Fixes Execution: optimize transcript search allocation (PR #897) #908