fix(web): align browse button and select chevrons

[techotaku39]

Summary

• Stretch the New Session Browse button to match the adjacent directory input height.
• Add a shared SelectControl with an inset chevron and reserved right-side text space while preserving native select behavior.
• Use the shared control for all web selects so the indicator spacing stays consistent across New Session, Workspace Browser, Codex session sync, and voice settings.

Problem

The New Session directory row rendered the Browse button shorter than the directory input. Native select indicators were also positioned by the browser and sat too close to the right edge, including the other selects on the same page and elsewhere in the web app.

Testing

• bun typecheck
• bun run test:web (197 files, 1,717 tests)
• bun run test:shared (152 tests)
• bun run build
• Manual smoke test on the mobile New Session layout via the local production build

AI disclosure

This change was implemented and reviewed with OpenAI Codex.

[github-actions]

Findings

• No findings.

Summary
Review mode: initial
No issues found in the added or modified lines. Residual risk is limited to browser-specific native select rendering and responsive visual alignment; the PR includes component/unit coverage, while repository CI passed.

Testing

• Not run locally (automation); the repository test check passed for the reviewed head.

HAPI Bot

[github-actions]

Findings

• No findings.

Summary
Review mode: follow-up after new commits
No issues found in the added or modified lines. Residual risk remains browser-specific select rendering and responsive visual alignment: the added tests verify classes, wrapper sizing, and native change behavior, but not actual rendering in mobile/desktop browsers.

Testing

• Not run (automation); the repository test check was still in progress at review time.

HAPI Bot