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/helpers/auq-sdk-capture.ts

@@ -402,12 +402,6 @@ export function verboseSkill(): string {
   );
 }
 
-function execGit(args: string[]): string {
-  const r = spawnSync('git', args, { cwd: ROOT, encoding: 'utf-8', maxBuffer: 64 * 1024 * 1024, timeout: 30_000 });
-  if (r.status !== 0) throw new Error(`git ${args.join(' ')} failed: ${r.stderr}`);
-  return r.stdout;
-}
-
 /**
  * Capture the real mode-selection tool input, without answering the question.
  * Print mode retains the existing 12-turn cap; interactive CLI max-turns is