fix: guard summary and score display on parseFailed analysis

[pi3-code]

Summary

Follow-up to #65. When analysis parsing fails, the stub object has all-zero scores — but printAnalysisSummary and printScoreSummary still ran, showing misleading "STRATEGY ASSESSMENT" bars and KSM scores of 0.0 right after the spinner already warned about the parse failure.

• Guard all four printAnalysisSummary call sites to skip when parseFailed is true
• In analyze.ts multi-run mode, show Score: N/A (parse failed) instead of silent skip
• In results-flow.ts, show retry message when user selects "View analysis" on a failed parse
• Add export.test.ts covering promptExport for undefined, parseFailed: true, parseFailed: false, and valid analysis

Files changed:

• src/commands/run.ts — guard summary + score block
• src/interactive/run-flow.ts — guard summary + score block
• src/commands/analyze.ts — guard summary + add N/A fallback for multi-run
• src/interactive/results-flow.ts — guard interactive "View analysis" menu action
• tests/unit/export.test.ts — new (4 tests)

Test plan

• npm run build — clean
• npx vitest run — 415/415 pass (including 4 new export tests)
• Manual: run a benchmark, corrupt the analysis JSON, verify no zero-score summary prints
• Manual: oasis analyze on multiple runs with one corrupted — verify Score: N/A (parse failed) appears

[Treelovah]

Good follow-up to #65. This catches the other half of the problem — the zeroed-out strategy bars and 0.0 KSM score that still printed even after the export prompt was gated. All four callsites guarded, multi-run N/A fallback is clean, and the export tests cover the change from #65 too.