Platform Setup Canonical Route Preservation

Purpose

Keep /ops/platform-setup/* as a stable canonical route family while the shared setup/topology cutover continues.
Preserve bookmarked operator entry points without forking the actual setup behavior into a second product shell.

Owner shell:
- Ops > Platform Setup
Preserved canonical leaf routes:
- /ops/platform-setup
- /ops/platform-setup/regions-environments
- /ops/platform-setup/promotion-paths
- /ops/platform-setup/workflows-gates
- /ops/platform-setup/gate-profiles
- /ops/platform-setup/release-templates
- /ops/platform-setup/policy-bindings
- /ops/platform-setup/defaults-guardrails
Shared setup/trust destinations still owned elsewhere:
- /setup/topology/*
- /setup/trust-signing

ops/platform-setup/* must render their intended platform-setup pages without rewriting the browser URL to setup/topology/*.
Explicit drill-ins into the broader topology product may still link to /setup/topology/* when the destination has no canonical ops/platform-setup equivalent.
trust-signing stays a redirect into Setup > Trust & Signing; it is not owned by Platform Setup.

Keep:
- stable operator bookmarks for legacy platform-setup leaves
- the lighter platform-setup summaries for regions, promotion paths, workflows, and gate profiles
- a clear distinction between the Ops > Platform Setup handoff shell and the broader Setup > Topology workspace
Why:
- these leaves are still referenced from live setup and ops surfaces
- the defect was URL drift, not missing product value

Replaced redirect-only platform-setup topology leaves with mounted canonical pages.
Updated Platform Setup home quick links to stay on /ops/platform-setup/*.
Repaired stale page-local /platform/setup/* and /topology/* links to either canonical platform-setup leaves or valid setup/topology drill-ins.
Added focused Angular and Playwright regression coverage for preserved canonical URLs.