test: delete tests of dead eval code (A)

- A1: the retired Eng lexical oracle (evaluateEngSeedCoverage,
  isEngSeedDecisionAUQ), the completion-handoff detector and the retained
  corpus had no paid caller since v1.87.6; delete their 26 replay files,
  ~2.6k helper LOC and fixtures, and the dead blocks in 8 mixed files
  (live hasNativePlanTerminal / batching assertions stay).
- A2: dead viewport approvers in autoplan-artifact-permission and their 11
  replay files + fixtures; recorder/launcher cases stay.
- A3: never-wired oracles and seeders (autoplan-phase-order,
  eng-finding-fixture, ceo-paired-fixture, design-ui-scope,
  plan-skill-completion, pty-current-screen, required-reads,
  transcript-section-logger); plan-seed-submission now decodes through the
  production createPtyScreen; section manifests name their actual guard.
- A4: zero-reference helper exports, plus execGit and invokeAndObserve
  found by the reachability pass.
- 52 fixtures orphaned by the deletions; touchfile and selection-table
  entries for every deleted path.

test/touchfiles.test.ts

@@ -113,7 +113,7 @@ describe('selectTests', () => {
     },
   );
 
-  test.each(['test/helpers/owned-claude-transcript.ts', 'test/helpers/plan-skill-completion.ts'])(
+  test.each(['test/helpers/owned-claude-transcript.ts'])(
     'native completion changes select the Design UI gate: %s', (file) => {
       const result = selectTests([file], E2E_TOUCHFILES);
       expect(result.selected).toContain('plan-design-with-ui-scope');