Flip react-router-dom-v5-compat to v6

[blaipr]

⚠️⚠️⚠️ Depends on #489 — please merge #489 first.

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SUMMARY

Flip react-router-dom from v5 + the react-router-dom-v5-compat bridge to react-router v6 proper, completing Step 2 of the React modernization. Every screen <Switch> route tree is already v6 and the whole test suite is RTL, so the compat bridge is no longer needed.

Production changes

• App.js: remove <CompatRouter> — the v6 <HashRouter> wraps <App> directly.
• Retarget ~340 react-router-dom-v5-compat imports → react-router-dom.
• Replace the v5-only APIs the compat layer had been shimming (which v6 drops):
  • ScreenHeader breadcrumbs: rewrite the recursive v5 <Route>/useRouteMatch walk as a plain useLocation() + cumulative-path lookup (breadcrumbConfig is keyed by resolved paths, so no route matching is needed).
  • useRouteMatch → useMatch (Setting AzureAD/LDAP/GitHub detail+edit, Subscription, Config, UserAndTeamAccessAdd) or location.pathname (Project/WorkflowApproval lists); <Redirect> → <Navigate>; matchPath → v6 signature.
  • <Link innerRef> → ref (v6 Link is forwardRef).
• react-router-dom ^5.3.3 → ^6.30.4; remove react-router-dom-v5-compat.
• history 4.10.1 → ^5.3.0 (devDependency — v6's <Router> needs the v5 listen signature, and v6 no longer pulls history itself; only the test harness uses it directly).

Test harness

• testUtils/rtlContexts.js: replace the v5-Router + nested-v6 CompatV6Layer with a single v6 history-driven <Router> (an inlined HistoryRouter).
• Convert the router-using test suites to v6 (<Switch>/standalone <Route> → <Routes> + element, manual <Router history> → renderWithContexts, useHistory → useNavigate, mount useMatch/useParams components at concrete v6 URLs). No production assertions weakened; no new skips.

ISSUE TYPE

• New or Enhanced Feature

COMPONENT NAME

• UI

ASCENDER VERSION

awx: 25.4.1.dev110+g8e7ecff748

ADDITIONAL INFORMATION

Stacked on #489 (the JobOutput @tanstack/react-virtual swap) to avoid a package.json/JobOutput.js conflict; once #489 merges this rebases cleanly to drop that commit.

Verification

• npm --prefix awx/ui run test: 552 suites / 2910 tests green (3 pre-existing documented skips); npm --prefix awx/ui run lint clean; npm --prefix awx/ui run build (production) compiles clean; test_licenses.py green (removed the orphaned react-router-dom-v5-compat license).
• Browser-verified on a dev instance (headless Chrome, ~55 routes/flows), all with 0 /api/v2/.../undefined/... calls:
  • all routes render (no Not Found / blank / error overlay); breadcrumbs render + navigate; tab navigation incl. nested sub-tabs (inventory Hosts/Groups/Sources); useMatch detail pages (GitHub/Azure/LDAP detail + edit) render without redirect loops.
  • navigate-on-submit: create org → redirect to its detail, edit → redirect, delete from list → removed; 404 catch-all; logout → /login, protected route while logged out → /login, re-login → /home; browser back/forward.

Note: v6 emits benign v7_startTransition / v7_relativeSplatPath future-flag console warnings — harmless; opting into them belongs with the react-router 7 step.

[Copilot]

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[blaipr]

Superseding this in favor of a 3-part split so the changes are reviewable in pieces (this single PR was 373 files, over Copilot's 300-file review limit, so it never got an automated review).

The v6 flip is inherently atomic because react-router-dom-v5-compat peer-requires react-router-dom v4/5 and cannot coexist with v6. To split it anyway, the new series introduces a one-line src/routerCompat re-export module, routes every consumer through it in two mechanical passes, then flips that single module to v6 last:

• react-router v6 flip (1/3): route imports through a routerCompat module #494 (1/3): introduce routerCompat, retarget the first half of the imports
• react-router v6 flip (2/3): route remaining imports through routerCompat #495 (2/3): retarget the remaining imports
• react-router v6 flip (3/3): repoint routerCompat at v6, remove the compat shim #496 (3/3): repoint routerCompat at react-router-dom v6, bump the package, remove the compat shim, convert the remaining v5-only APIs

Each part is under 300 files, individually Copilot-reviewable, and leaves the app working and the suite green. Same end state as this PR (lint clean, 552 suites green, production build clean, test_licenses green). Closing this one.