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+# Single Source Consolidation Full-Scope Follow-Through
+
+## Context
+
+This document supersedes the scoped execution boundary of
+[`2026-03-22-single-source-consolidation-pr1.md`](./2026-03-22-single-source-consolidation-pr1.md)
+for PR #244. The PR1 document remains a historical snapshot of the initial
+landing slice. This document captures the expanded branch-wide finish that
+continued until the single-source, workflow, schema, and web admin duplication
+themes were fully closed for this PR.
+
+## Goals
+
+- Eliminate active double-source implementations for proxy protocols and runtime headers.
+- Centralize account, OAuth, route refresh, and platform discovery workflows.
+- Collapse schema metadata normalization and feature compatibility drift points.
+- Remove repeated web admin page scaffolding and large inline modal/panel implementations.
+- Finish the branch in a merge-ready state with focused regressions and formal builds.
+
+## Scope Delivered In This Branch
+
+### Server and Shared Runtime
+
+- OpenAI Responses normalization and conversion now flow through one shared implementation boundary.
+- Shared proxy surface orchestration owns retry recovery, success bookkeeping, and surface-level failure handling.
+- Provider header/body runtime shaping is centralized behind provider profiles and shared header utilities.
+- OAuth identity now treats structured columns as the canonical source, with compatibility/backfill isolated to a removable layer.
+- Route refresh and rebuild sequencing flows through `routeRefreshWorkflow`, not controller-local orchestration.
+- Platform discovery moved out of `modelService` into dedicated registry-backed discovery modules.
+- Schema metadata normalization is shared by contract and introspection code paths.
+- Legacy schema compatibility derives feature-owned allowances from feature specs instead of maintaining a second whitelist.
+
+### Web Admin
+
+- Token-route, brand, and downstream client display rules now rely on shared helpers and registries instead of page-local duplicates.
+- `ResponsiveBatchActionBar` centralizes repeated batch action shells across admin list pages.
+- `ResponsiveFilterPanel` centralizes the responsive "desktop controls vs mobile sheet" scaffold across admin pages.
+- `Settings`, `Accounts`, `ModelTester`, and `DownstreamKeys` no longer keep their heaviest modal or drawer UIs inline in the page file.
+- Brand matching metadata is owned by `brandRegistry`, with `BrandIcon` reduced to rendering concerns.
+
+## Commit Groups
+
+### Protocol and Workflow Consolidation
+
+- review-driven cleanup commits
+- OAuth identity and route refresh workflow commits
+- downstream client/runtime header/profile consolidation commits
+- platform discovery extraction commits
+
+### Schema and Shared Contract Consolidation
+
+- shared schema metadata normalization
+- legacy schema compatibility derivation from feature specs
+- shared token-route contract and pattern ownership
+
+### Web Admin Decomposition
+
+- responsive batch action scaffold
+- responsive filter scaffold
+- settings modal extraction
+- accounts model management modal extraction
+- model tester panel extraction
+- downstream key drawer extraction
+
+## Final Verification Matrix
+
+Run these groups before calling the branch complete.
+
+### Protocol and Surface
+
+- `npm test -- src/server/proxy-core/surfaces/sharedSurface.test.ts src/server/routes/proxy src/server/transformers/openai/responses src/server/transformers/anthropic/messages src/server/services/proxyInputFileResolver.test.ts`
+
+### OAuth, Workflow, and Platforms
+
+- `npm test -- src/server/routes/api src/server/services/accountMutationWorkflow.test.ts src/server/services/modelService.discovery.test.ts src/server/services/oauth/oauthAccount.test.ts src/server/services/platforms/standardApiProvider.test.ts src/server/services/platforms/llmUpstream.test.ts`
+
+### Schema
+
+- `npm run test:schema:unit`
+- `npm run schema:contract`
+- `npm run smoke:db:sqlite`
+
+### Web and Build
+
+- `npm test -- src/web/pages/responsiveFilterPanel.architecture.test.ts src/web/pages/checkin.mobile.test.tsx src/web/pages/logs.mobile.test.tsx src/web/pages/programLogs.mobile-layout.test.tsx src/web/pages/accounts.batch-actions.test.tsx src/web/pages/sites.mobile-actions.test.tsx src/web/pages/tokens.batch-actions.test.tsx src/web/pages/DownstreamKeys.test.tsx src/web/pages/DownstreamKeys.mobile.test.tsx src/web/pages/downstreamKeys.mobile-layout.test.tsx src/web/pages/tokenRoutes.mobile-layout.test.tsx src/web/pages/tokenRoutes.mobile.test.tsx src/web/pages/models.mobile-layout.test.tsx`
+- `npm run build`
+
+## Done Definition
+
+The branch is complete when:
+
+- no page under `src/web/pages` imports `MobileFilterSheet` directly;
+- no active protocol path keeps parallel single-source conversions alive;
+- controller layers do not own route rebuild choreography;
+- schema metadata and compatibility rules do not keep a second handwritten truth source;
+- focused regressions and formal builds pass from the commands above.