test(e2e): Playwright smoke tests for six authenticated pages (#1897)

[bokelley]

Closes #1897

Extends the Playwright smoke-test suite (introduced in #1895) to six additional authenticated pages. Extracts shared login/assert/error-collection utilities from profile-edit.smoke.js into a tests/e2e/helpers.js module, then adds one smoke file per page:

File	Route	Dev users
membership-hub.smoke.js	/membership/hub	member, personal, admin
organization-dashboard.smoke.js	/organization	admin, member
certification.smoke.js	/certification	personal, admin
brand-viewer.smoke.js	/brand/:domain	admin (known domain + unknown domain error state)
community-hub.smoke.js	/community	personal, member
admin-newsletter.smoke.js	/admin/newsletters/the_prompt (+ redirect from /admin/digest)	admin

Each test: dev-login → navigate → wait for key container → assert critical DOM IDs → collect console errors. Screenshot on failure to /tmp/.

Non-breaking justification: adds new .js test files outside the TypeScript compilation boundary; no existing code modified; changeset --empty (no protocol impact).

Note on runner script: npm run test:e2e (mentioned in the issue) requires a package.json script entry which cannot be added in this PR. Tests run today as node tests/e2e/<file>.smoke.js matching the existing profile-edit.smoke.js pattern.

Note on pre-existing build failures: npm run build has pre-existing TypeScript errors in server/src/validator.ts and url-security.ts (confirmed present on main before this branch). These are unrelated to this PR; npm run build:schemas passes clean.

Pre-PR review:

• code-reviewer: approved after fixes — removed resetFailures() from inside per-userType loops (was silently discarding non-last-iteration failures) and dropped unused resp variable in admin-newsletter redirect check
• adtech-product-expert: approved — pattern proven, all 6 target pages confirmed in server/public/, changeset --empty correct, CI integration deliberately excluded as a follow-on

Triage-managed PR. This bot does not currently iterate on
review comments or PR conversation threads (only on the source
issue). To unblock:

• Push fixup commits directly: gh pr checkout <num> →
  fix → push.
• Or re-trigger: comment /triage execute on the source
  issue.

See #3121
for context.

Session: https://claude.ai/code/session_016dJ4nMXCbcLEmCsCNrBK6d

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