fix: updates in diagnosis report + submit report button

[Imod7]

Description

• The diagnosis screen and its exported report mark skipped methods as failed (with the reason they were skipped), so every truapi method appears in the compatibility matrix instead of being dropped.
• The "Submit report" button keeps the issue URL under GitHub's length limit (full report to the clipboard, compact variant in the URL).
• Also fixes a broken example payload that made one signing method fail to load on a phone.

Changes

• playground/src/lib/auto-test.ts - skipped methods carry a short reason ("service not yet wired up by hosts" / "host surface intentionally deferred") so the Details column isn't empty.
• playground/src/lib/diagnosis-report.ts - the report has a N success · N failed summary line; skipped methods are listed as failed (❌) with their reason so they stay in the compatibility matrix (the aggregator keeps only ✅/❌ cells). Adds a compact mode (drops success details) and a URL-length cap: if the report is still too big, the issue opens with a "paste from clipboard" note instead of failing.
• playground/src/components/DiagnosisView.tsx - the on-screen diagnosis shows skipped methods as failed with their reason; the summary is N success · N failed. "Submit report" copies the full report to the clipboard and puts the compact variant (success details dropped) in the issue URL.
• rust/crates/truapi/src/api/signing.rs - fixes the sign_payload_with_legacy_account example, which used an incomplete call payload the phone couldn't decode ("fails to load"). Now uses the same valid payload as sign_payload.
• playground/tests/e2e/dotli-diagnosis.ts - the e2e hard-fail gate excludes intentionally-skipped rows (data-skipped), so only genuine failures fail the run.
• playground/CLAUDE.md - updates the file descriptions to match the above.

Notes

• Skipped methods appear as failed (❌) in the compatibility matrix, so every truapi method stays in the grid; the reason a method was skipped is preserved in the report's Details column. In the matrix grid an intentional skip and a genuine failure look identical — the distinction only survives in the Details column.
• The full report is always on the clipboard, so nothing is lost when the URL falls back to the paste note.