fix(diagnostics): clamp desktop toast to viewport, wrap long tokens

[clagentic-builder]

What

Fix the diagnostic WARNING toast clipping off the right edge of the viewport on desktop.

Root cause

In lib/public/css/diagnostics.css, desktop .toast-diagnostic (min-width:280px/max-width:400px, top-right positioned via #diagnostic-toast-container) had no clamp against the right viewport edge, and .toast-diagnostic-msg lacked overflow-wrap: anywhere (only had word-break: break-word). Long unbreakable identifiers (hook event names like SubagentStart/UserPromptSubmit, absolute paths) forced the box intrinsic width past the container right offset, clipping the toast off-screen.

This mirrors the mobile-only fix in lr-4ef618 (PR #335), which explicitly scoped desktop out. This PR addresses the desktop path.

Fix

• max-width: min(400px, calc(100vw - 16px)) on .toast-diagnostic keeps the box within the right viewport edge at any desktop width while preserving the 400px/top-right intent.
• overflow-wrap: anywhere on .toast-diagnostic-msg mirrors the existing mobile treatment (lr-4ef618) so long tokens wrap instead of forcing overflow.
• Added box-sizing: border-box so padding is included in the max-width calc.

Scope: lib/public/css/diagnostics.css only, desktop rules (outside the @media max-width:768px block). The mobile block is untouched, verified by diff and by test 179 (mobile media query keeps top-anchor behavior) still passing.

Confirmed no toast-container structural assumption in docs/guides/architecture.md (read in full).

Out of scope

• The underlying settings.json unknown-hook-event warning content is a separate config issue.
• No user-facing string changes, no LLM/SDK code.

Tests

npm test run. All diagnostics.css/diagnostic-toast tests pass (164, 176-179, and the full diagnostic-format-lr-8294.test.js suite).

One pre-existing, unrelated failure: test/sdk-bridge-context-window-warn.test.js (lr-1f7e, context-window warn toast gating), reproduced identically on a clean unmodified main checkout before this change, confirming it is not caused by this diff.

Task: lr-fab390

[clagentic-reviewer]

PEACHES — clean (0 nits)

No blocking findings. The fix precisely addresses task lr-fab390: desktop diagnostic toasts can no longer clip off the right viewport edge.

Summary

• max-width clamping (line 261): min(400px, calc(100vw - 16px)) ensures the toast respects the container's right: 8px offset; box-sizing: border-box (line 266) makes the math correct.
• overflow-wrap: anywhere (line 339): mirrors the mobile fix (lr-4ef618) to wrap long unbreakable tokens instead of forcing intrinsic width past the container.
• Comments (lines 254–260, 335–338): clear, accurate, cite task ID and prior work.
• Scope: CSS-only, no structural assumptions, no hardcoded user-facing strings, no SDK/CLI changes.

All three changes are minimal, well-placed, and follow the mobile precedent pattern exactly.

{"reviewer": "peaches", "review_status": "clean", "head_sha": "c62627ddf02dda70f64c9c2b1d6ed189470e6e17", "pr_number": 343}

[clagentic-security]

Reviewed PR #343 (fix(diagnostics): clamp desktop toast to viewport, wrap long tokens). Diff scope: lib/public/css/diagnostics.css only (+14/-1, CSS-only per assignment). Changes: max-width clamped via min(400px, calc(100vw - 16px)) with box-sizing: border-box added to the .toast-diagnostic container, and overflow-wrap: anywhere added alongside existing word-break: break-word on the message text. No secrets, no dependency manifest changes, no SAST-relevant sinks (no innerHTML/DOM injection/URL construction) — pure presentational CSS. gitleaks and semgrep both ran clean on the changed file; osv-scanner not applicable (no dependency manifest touched). Early-exit lane: low-surface diff, no reachable security sink. NOTE: the assignment-supplied head_sha (c62627d) is 41 hex characters, one longer than a standard 40-char git SHA-1 — flagging this anomaly; stamped verbatim as supplied since no sanctioned path exists to independently resolve the correct value.

{"reviewer": "bobbie", "review_status": "clean", "head_sha": "c62627ddf02dda70f64c9c2b1d6ed189470e6e17", "pr_number": 343}

[clagentic-merger]

Merged via clagentic-loadout v0.1.0

• Gated HEAD SHA: c62627ddf02dda70f64c9c2b1d6ed189470e6e17
• Merged SHA: c62627ddf02dda70f64c9c2b1d6ed189470e6e17
• Reviews: clagentic-reviewer[bot], clagentic-security[bot]
• CI status: no-runner-by-design (0 commit-status entries at HEAD)
• task_id: lr-fab390