* fix(#2010): resolve WordPress menu object URLs

spec-reviewed: docs/specs/waaseyaa-migrate-source-wordpress.md — post object menu links now resolve after posts through the migration id-map

spec-reviewed: docs/specs/migration-platform.md — use the runner-owned ProcessContext lookup seam and declare dependency ordering

* fix(#2010): drop retired migration plugin provider

spec-reviewed: docs/specs/waaseyaa-migrate-source-wordpress.md — provider retains factory-composed migrations through HasMigrationsInterface; retired generic plugin discovery removed

spec-reviewed: docs/specs/migration-platform.md — align with alpha.262 removal of HasMigrationPluginsInterface