refactor(packages): extract model-core package

.omo/evidence/task-3-di-interface.txt

@@ -0,0 +1,19 @@
+Task 3 ProviderCache interface evidence
+
+Defined interface:
+
+- `packages/model-core/src/provider-cache.ts`
+  - `readConnectedProvidersCache(): string[] | null`
+  - `findProviderModelMetadata(providerID: string, modelID: string): ModelMetadata | undefined`
+
+Injection points:
+
+- `packages/model-core/src/model-resolution-pipeline.ts`
+  - `resolveModelPipeline(request, providerCache)` uses `providerCache.readConnectedProvidersCache()`.
+- `packages/model-core/src/model-error-classifier.ts`
+  - `selectFallbackProviderWithCache(providers, providerCache, preferredProviderID?)` uses `providerCache.readConnectedProvidersCache()`.
+
+Adapter wiring in OMO:
+
+- `src/shared/model-resolution-pipeline.ts` passes `connectedProvidersCache` into model-core resolver.
+- `src/shared/model-error-classifier.ts` passes `connectedProvidersCache` into model-core provider selection.

.omo/evidence/task-3-no-coupling.txt

@@ -0,0 +1,8 @@
+Task 3 no-coupling evidence
+
+- Extracted model resolution files into `packages/model-core/src` and replaced original `src/shared/*` with per-file shims.
+- `packages/model-core/src/model-resolution-pipeline.ts` now accepts `providerCache: ProviderCache` and no longer imports `src/shared/connected-providers-cache` directly.
+- `packages/model-core/src/model-error-classifier.ts` exposes `selectFallbackProviderWithCache(...)` and supports cache injection.
+- OMO call-sites receive cache injection through shared adapters:
+  - `src/shared/model-resolution-pipeline.ts` injects `src/shared/connected-providers-cache` into model-core.
+  - `src/shared/model-error-classifier.ts` injects `src/shared/connected-providers-cache` into model-core.

.omo/evidence/task-3-tests.txt

@@ -0,0 +1,8 @@
+Task 3 verification evidence
+
+- `bun run typecheck` => exit 0
+- `bun test` => `7312 pass / 1 skip / 2 fail / 7315 total` (matches baseline)
+- `bun run build` => exit 0
+
+Notes:
+- The 2 failures are pre-existing baseline failures in `src/features/opencode-skill-loader/skill-content.test.ts`.

.omo/notepads/package-layering-refactor/learnings.md

@@ -53,3 +53,13 @@
   - `bun run typecheck` exit 0
   - `bun test` 7312/1/2/7315 (baseline-matching drift)
   - `bun run build` exit 0
+
+## [2026-05-21T00:00:00Z] Task 3 retry (worktree)
+- Extracted model resolution pipeline surface into `packages/model-core/` with moved sources/tests and package scaffold (`package.json`, `tsconfig.json`, barrel `src/index.ts`).
+- Added ProviderCache DI seam in model-core:
+  - `model-resolution-pipeline.ts` accepts `providerCache`.
+  - `model-error-classifier.ts` exposes cache-injected provider selector.
+- Kept OMO runtime cache implementation in `src/shared/connected-providers-cache.ts` and wired injections through shared shims.
+- Recreated per-file `src/shared` shims with explicit symbol re-exports (no `export *` in shims).
+- Moved `src/shared/model-capabilities/` subtree into model-core and kept shared adapter entry via `src/shared/model-capabilities/index.ts` wrapper.
+- Verification pass: `bun run typecheck`=0, `bun test`=7312/1/2/7315 baseline, `bun run build`=0.