fix(web): expose error disclosure state

[saphid]

What Changed

Long diagnostic/provider errors could expand visually without exposing their expanded state to assistive technology. Connect the existing native button to a unique text-region ID and expose aria-expanded.

Verification

Refreshed against upstream main 761d4bac1c238ea7af4dd36b56719ad5e30771c3. Fresh targeted lint, web typecheck, and git diff --check origin/main...HEAD pass. The PR component file is byte-for-byte unchanged from the previously captured candidate, so the existing evidence still demonstrates this contribution; it has not been relabeled as a fresh capture. Refresh performed by GPT-6 Astra in the Codex harness. Fresh independent Claude review is unavailable: claude auth status reports signed out.

Actual component with synthetic long error: browser accessibility tree changes expanded=false to true, full text is revealed, and collapse restores false. Targeted lint/format and combined web typecheck pass.

Isolated rendering of the production component, not a live provider failure. OS screen-reader speech and native keyboard activation were not verified; preview key injection was unreliable. Existing native button behavior is unchanged.

Real-client accessibility verification

Fresh pass in the actual Settings → Diagnostics page, September 6. Base b2e15185aee22bfdee78806f2734b0a4de9c2c77; candidate 6b1a09fe7e79a1a6c5063e0de658132a832e131d. Same long diagnostic text, 1280×800 dark web client and isolated backend. The diagnostic record is seeded test data; the full application reads it through its normal diagnostics endpoint.

Observed DOM state	Base	Candidate
Collapsed error	aria-expanded absent; aria-controls absent	aria-expanded=false; controls resolves to the error text
After Show full error	Text unclamped; both attributes absent	Text unclamped; aria-expanded=true; same valid target
After Show less	Text reclamped	Text reclamped; aria-expanded=false; same valid target

The actual app's button was clicked to expand and collapse on both revisions. This closes the integrated component-state gap. OS screen-reader speech and separate Electron/native mobile sessions were not tested.

The screenshot provides app context. The before/after DOM observations above prove the nonvisual change; no appearance GIF is used. No executable code changed during this evidence pass. Verified by GPT-6 Astra in the T3 Code Codex harness.

Checklist

• Small, focused change
• Problem and verification explained
• Nonvisual accessibility evidence and integration limitation explained

Implemented by GPT-6 Astra medium task workers, reviewed and verified by GPT-6 Astra in the T3 Code Codex harness. Direct cross-provider review attempted with claude --model claude-opus-5 --effort high --permission-mode plan --tools Read,Glob,Grep --output-format json -p …; exit 1 because OAuth expired. No Claude model ran.

Note

Expose aria-expanded and aria-controls on ExpandableText toggle button

Adds React's useId hook to generate a unique identifier for the text container in ExpandableText.tsx. The toggle button now links to the text element via aria-controls and reports its expanded state via aria-expanded.

^{Macroscope summarized 6b1a09f.}

Current-base verification

Updated to upstream main b2e15185aee22bfdee78806f2734b0a4de9c2c77 at b28625a05650bed1bc478c540ef122162b4dd084. All 3 applicable focused verification commands passed. Earlier runtime observations and media retain their stated revisions and limitations; these fresh runs do not constitute new client recordings. Fresh independent Claude review is unavailable because its OAuth credentials have expired. Refreshed by GPT-6 Astra in the Codex harness.

Latest head 6b1a09fe7e79a1a6c5063e0de658132a832e131d is a no-code-change commit to refresh a stale GitHub status: workflow 34013326788 reported success, while its Test check remained in progress after all steps passed. The source tested above is unchanged.

[macroscopeapp]

Approvability

Verdict: Approved at d8a9464

Macroscope's review found this PR approvable — This is a focused accessibility fix that links the existing disclosure button to its text and exposes the current expanded state. It is confined to one component and does not materially alter existing runtime behavior.

^{You can add or adjust custom eligibility rules. Learn more.}

[t3-code]

reviewed diff and relevant surrounding code at 6b1a09fe7e79a1a6c5063e0de658132a832e131d. no blocking findings.

the generated id is stable per component and the disclosure reports the same state that controls clamping. no code changes needed. i did not rerun a browser or screen reader.

ci snapshot: no failing or pending checks; some checks are skipped. this is a comment review, not an approval or merge.