fix: allow overriding the verify row-shape top-level key cap

[ayushsingh82]

Summary

• validateRowShape() (src/browser/verify-fixture.ts) already accepted an optional maxTopLevelKeys, but webcmd browser verify never exposed a way to set it — it always called validateRowShape(rows) with the hardcoded 12-key default. Any adapter whose rows are wide by design (the shipped 52-column university course-export adapters, for example) could never pass verify regardless of correctness.
• Adds a --max-top-level-keys <n> flag to browser verify, validated as a positive integer, threaded through to validateRowShape(rows, { maxTopLevelKeys }). Default behavior (12) is unchanged when the flag is omitted.
• Updates the failure message to reflect the actual configured cap and to point authors at the new flag.
• Updates the adapter-author skill's fixture checklist (Step 12) so agents building wide-row adapters know to use --max-top-level-keys instead of skipping the required verify fixture.

Fixes #218

Test plan

• Unit: validateRowShape respects a raised maxTopLevelKeys and still rejects keys beyond it (src/browser/verify-fixture.test.ts)
• Integration: browser verify rejects a 20-key row by default, passes with --max-top-level-keys 20, and rejects a non-positive value with a usage error (src/cli.test.ts)
• npm run typecheck clean
• npm test — 385 test files / 4625 passed, 1 skipped (unchanged skip, +3 new passing tests)

Note for maintainers

While verifying test coverage for this fix I noticed vitest.config.ts's unit project excludes src/browser/**/*.test.ts entirely (added in the #216 plugin-migration merge), and no other configured project or CI job covers that glob either — so all 44 test files under src/browser/ (including verify-fixture.test.ts, cdp.test.ts, analyze.test.ts, etc.) currently don't run in CI. That's unrelated to this fix, so I'm not touching vitest.config.ts here, but wanted to flag it — happy to file a separate issue if useful.

[github-actions]

🟢 No documentation gap found — medium confidence

The automated review found no documentation gap in the supplied changes.

This review is advisory and does not block merging.

[ayushsingh82]

@ngaurav Fixed — this PR adds a --max-top-level-keys <n> override to webcmd browser verify so wide-row adapters (like the 52-column university course-export adapters) can pass verify, closing #218.