[codex] Fix Firefox message reply overflow and other compose area issues

[guaka]

What changed

• Bounds the message thread flex layout so Firefox can shrink the message list instead of pushing the reply composer below the viewport.
• Keeps the reply editor internally scrollable after a capped height while leaving the send controls visible.
• Adds a targeted Firefox Playwright project and regression test for the long-reply overflow case.
• Updates the e2e browser setup so Firefox is available in CI alongside Chromium.

Fixes #2722

Validation

• npm run test:client -- ThreadReply
• bash -n scripts/e2e/test-e2e.sh
• npx eslint modules/messages/client/components/Thread.component.js modules/messages/client/components/ThreadMessages.js modules/messages/client/components/ThreadReply.js playwright.config.js tests/e2e/test.js tests/e2e/messages-layout.spec.js
• TRUSTROOTS_E2E_SKIP_COVERAGE_REPORT=true npm run test:e2e -- --project=messages --project=messages-firefox-layout --grep "reply editor remains usable"

Notes

• The full e2e suite was also attempted. The new messages-firefox-layout test and the existing messages project passed, but the full run ended with unrelated public/auth/member failures and later ENOSPC: no space left on device errors after generating large Playwright artifacts locally.

[github-actions]

E2E screenshots

Run: https://github.com/Trustroots/trustroots/actions/runs/29268773056

messages-firefox-layout-reply editor remains usable when long text overflows

setup-authenticated-create admin storage state

setup-authenticated-create authenticated storage state

setup-authenticated-create seeded member storage state

[github-actions]

trustroots@0.3.3 coverage:pr-summary
node ./scripts/coverage/generate-pr-summary.js

Coverage overview

Status: Passing

Suite	Status	Recorded	Result	Report
Client	✓	2026-07-05 18:25 Duration 3m 01s	Statements 🟢 100.00% Branches 🟢 100.00% Functions 🟢 100.00% Lines 🟢 100.00%	coverage-client
Server	✓	2026-07-05 18:24 Duration 1m 34s	Statements 🟢 100.00% Branches 🟢 100.00% Functions 🟢 100.00% Lines 🟢 100.00%	coverage-server
End-to-end	✓	2026-07-05 18:27 Duration 5m 22s	Tests 🟢 157/157 Pass rate 🟢 100.00% Areas 🟢 8/8 Features 🟢 97/97 Scenarios 🟢 236/236 Feature coverage 🟢 100.00% Scenario coverage 🟢 100.00%	playwright-report

End-to-end areas

Area	Status	Passed	Failed	Total
Admin	✓	20	0	20
Authentication	✓	17	0	17
Experiences	✓	8	0	8
Member flows	✓	53	0	53
Messages	✓	14	0	14
Nostr	✓	8	0	8
Public pages	✓	32	0	32
Seeded content	✓	5	0	5
Total		157	0	157

Full HTML overview: download the coverage-report artifact from this workflow run.

[guaka]

we might as well want to fix other stuff related to the compose area

• when going back with the cursor when there are multiple lines, weird stuff happens
• this came in through support: "In the edit box for reply to messages (differently from the one where i write now) it is not possible to use dead keys, and compose key, that lead to be impossible to write certain words in certain languages."