fix(ui): avoid crypto.randomUUID crash on LAN HTTP showcase (#332)

[w7-mgfcode]

Summary

Closes #332 — Reliability E3 of umbrella #380.

crypto.randomUUID() is only defined in secure contexts (HTTPS or localhost). On a plain-HTTP LAN origin (http://<lan-ip>:5173/showcase) it is undefined, and the direct call at RunHistoryStrip.tsx:75 threw TypeError: crypto.randomUUID is not a function during render at pipeline_complete — React unmounted the whole tree and the showcase white-screened while the backend pipeline finished fine.

Changes

• frontend/src/lib/uuid-utils.ts (new) — safeRandomUUID(): native crypto.randomUUID() when available → RFC-4122-v4 via crypto.getRandomValues() (not secure-context-gated, crypto-strong) → Math.random() last resort when Web Crypto is absent entirely.
• frontend/src/lib/uuid-utils.test.ts (new) — 3 cases covering all three paths (v4 regex + uniqueness).
• RunHistoryStrip.tsx — one-line swap to safeRandomUUID() (the render-phase append pattern is deliberate and untouched).
• RunHistoryStrip.test.tsx — regression case stubbing the LAN-HTTP crypto shape (getRandomValues only); proven to fail with the original TypeError when the fix is reverted.
• eslint.config.js — repo-wide no-restricted-properties guard banning direct crypto.randomUUID access (message points at the helper); the only sanctioned call site carries inline disables. Verified the rule bites: the unfixed call site fails pnpm lint with the new message.

No new npm dependency (uuid/nanoid rejected — ~25-line util for one call site, per product-vision dependency-light footprint). Zero backend changes.

Validation

• ✅ pnpm lint — clean (0 errors; 1 pre-existing react-hooks/incompatible-library warning in untouched data-table.tsx)
• ✅ pnpm test --run — 323/323 across 58 files (+4 new cases)
• ✅ npx tsc -b — zero errors in touched files
• ✅ Backend gates untouched: ruff / mypy / pyright clean, 1920 unit tests pass
• ✅ LAN-HTTP dogfood (umbrella fix(repo): platform reliability hardening — agents, config, ui, forecast #380 risk row) — headless Chromium at http://10.0.0.226:5173/showcase: isSecureContext=false, typeof crypto.randomUUID === 'undefined'; full demo_minimal run completed (16s, PASS); no white screen, zero page errors; "Recent runs" strip rendered; persisted id 8706c012-2014-439e-806c-e235481e228a matches the v4 shape via the fallback path.

Notes for reviewers

• pnpm tsc --noEmit is vacuous (solution-style root tsconfig type-checks zero files), and npx tsc -b already fails on dev with pre-existing noUncheckedIndexedAccess errors in unrelated files (ai-models-panel.tsx, forecast-chart.tsx, job-picker.tsx, demand-utils.test.ts). Both deserve their own issue; out of scope here.

Summary by Sourcery

Introduce a safe UUID generation utility for the frontend and use it to prevent showcase crashes in non-secure (plain-HTTP LAN) contexts.

New Features:

• Add a shared safeRandomUUID() helper that generates RFC-4122 v4 IDs with fallbacks when secure-context APIs are unavailable.

Bug Fixes:

• Prevent the RunHistoryStrip component from crashing on plain-HTTP LAN origins where crypto.randomUUID is undefined by switching to the safe UUID helper.

Enhancements:

• Add an ESLint restriction to forbid direct crypto.randomUUID usage across the frontend and guide developers to the safe UUID helper.

Documentation:

• Document the reliability work for non-secure-context UUID handling in a new PRP markdown file.

Tests:

• Add unit tests for the UUID helper covering native, getRandomValues-based, and Math.random-based paths, and a regression test ensuring RunHistoryStrip behaves correctly when crypto.randomUUID is unavailable.

[sourcery-ai]

Reviewer's Guide

Implements a safe UUID generation utility for non-secure browser contexts, wires it into the showcase run history component to prevent LAN-HTTP crashes, adds targeted tests, and enforces a lint rule to prevent future direct uses of crypto.randomUUID, along with documenting the reliability work item in a PRP file.

File-Level Changes

Change	Details	Files
Introduce a safe UUID helper with layered fallbacks and corresponding unit tests.	Add safeRandomUUID utility that prefers crypto.randomUUID, then falls back to an RFC4122 v4 implementation using crypto.getRandomValues, and finally to a Math.random-based generator when Web Crypto is unavailable. Implement unit tests covering all three code paths, using vitest global stubbing to simulate different crypto shapes and validating v4 format and basic uniqueness.	frontend/src/lib/uuid-utils.ts frontend/src/lib/uuid-utils.test.ts
Update RunHistoryStrip to use the safe UUID helper and guard against regressions in non-secure contexts.	Replace the direct crypto.randomUUID call in RunHistoryStrip with safeRandomUUID while preserving the render-phase append pattern. Extend RunHistoryStrip tests with a regression case that stubs crypto to the LAN-HTTP shape (getRandomValues only), ensuring history appends without crashing and IDs match the v4 pattern, and clear global stubs after each test.	frontend/src/components/demo/RunHistoryStrip.tsx frontend/src/components/demo/RunHistoryStrip.test.tsx
Enforce repository-wide linting to disallow direct crypto.randomUUID usage and document the reliability epic.	Add an ESLint no-restricted-properties rule for crypto.randomUUID across TypeScript files, with guidance to use safeRandomUUID instead and relying on an inline disable only at the helper call site. Add a PRP markdown document describing the reliability E3 effort, problem context, design, implementation blueprint, validation steps, and guardrails for this safe UUID fallback change.	frontend/eslint.config.js PRPs/PRP-reliability-E3-safe-uuid-non-secure-context.md

Possibly linked issues

• fix(ui): avoid crypto.randomUUID crash on LAN HTTP showcase #332: PR adds safeRandomUUID, updates RunHistoryStrip, tests, and lint rule to fix the LAN HTTP crypto.randomUUID crash described.

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