/admin/friction page (fleet friction-dashboard decision)

Fleet friction-dashboard decision (bs-mrlqhi9hhir): add /admin/friction page rendering the layered-views rollup (vFrictionTop worst-actions-last-7/30d, trend, top-affected-users via vFrictionByUser once PLUTO-558's effectiveUserId fix lands, drill-to-raw). Reuses existing server-table primitives. Admin-cap gated, same slug pattern fleet-wide. Goal per Elazar: agent queries ONE final view with a single SELECT instead of spending 50k tokens on schema exploration, and Elazar can visit the page directly. Rollup views themselves (vFrictionDigest/vFrictionTop/vFrictionByUser) + supporting indexes are db-pluto-cc's scope (Class-A DDL, own WI + fresh audit-pluto-ca pre-apply -- do NOT piggyback on PLUTO-557's existing PASS). Criteria widening (opt-in whitelist -> opt-out) stays an OPEN 3-way fleet design fork, not yet ready to implement -- coordinate with db-pluto-cc before building against final view shapes that may still change.