feat: add core SDK scaffold and migration preflight

.dependency-cruiser.js

@@ -0,0 +1,18 @@
+const path = require("node:path");
+
+/**
+ * Dependency-cruiser configuration for the Phase 0 SDK-boundary measurement.
+ * Keep TypeScript path aliases aligned with browser-extension/tsconfig.json.
+ */
+module.exports = {
+  forbidden: [],
+  options: {
+    doNotFollow: { path: "node_modules" },
+    baseDir: path.join(__dirname, "browser-extension"),
+    tsConfig: { fileName: path.join(__dirname, "browser-extension/tsconfig.json") },
+    webpackConfig: {
+      fileName: path.join(__dirname, "browser-extension/webpack/webpack.common.js"),
+      env: { TARGET_BROWSER: "chrome" },
+    },
+  },
+};

.gitignore

@@ -110,6 +110,11 @@ browser-extension/public/wasm/
 AGENTS.md
 # The rest of /docs/ stays ignored (scratch research/audit notes).
 /docs/*
+# SDK separation artifacts must travel with the repository; other /docs/ files
+# remain local scratch material.
+!docs/security-invariants.md
+!docs/sdk-migration/
+!docs/sdk-migration/**
 
 # integration-tests is a LOCAL-ONLY crate (v3 decode harness + onboarding docs +
 # golden corpus + per-protocol e2e). No production logic — kept out of git by the

browser-extension/default-bundles/day1-safety/package.json

@@ -1,15 +1,13 @@
 {
   "package": "day1-safety",
-  "title": "지갑 처음 켤 때 6",
+  "title": "지갑 처음 켤 때 5",
   "title_en": "Day-1 Safety",
   "version": "1.1.0",
   "audience": "트레이딩/Web3 입문자 — 지갑을 처음 설치하고 첫 승인·송금·스왑을 하는 사람",
-  "description": "모든 지갑 사용자가 반드시 마주치는 3가지 순간(승인/서명, 송금, 스왑)에서 가장 흔하고 가장 치명적인 사고만 막는 최소 필수 6종. 6개 모두 외부 의존 없이 순수 Cedar로 즉시 동작한다.",
+  "description": "모든 지갑 사용자가 반드시 마주치는 3가지 순간(승인/서명, 송금, 스왑)에서 가장 흔하고 가장 치명적인 사고만 막는 최소 필수 5종. 5개 모두 외부 의존 없이 순수 Cedar로 즉시 동작한다.",
   "source": {
     "repo": "errkat4up/DAMBI",
-    "branch": "feat/cedar_manifest",
-    "commit": "a052a76b",
-    "origin_fixtures": "crates/policy-engine/tests/fixtures/default_policies_v2/phase1"
+    "path": "browser-extension/default-bundles/day1-safety"
   },
   "policies": [
     {

docs/sdk-migration/FINDINGS.md

@@ -0,0 +1,58 @@
+# Phase 0 findings
+
+## F-001 — alias resolution needs the extension webpack aliases
+
+`browser-extension/tsconfig.json` declares `@lib/*` and `@background/*`, but
+the dependency graph is complete only when dependency-cruiser also consumes
+`browser-extension/webpack/webpack.common.js`.  With that configuration there
+are no unresolved alias imports.  The remaining unresolved edge is
+`backend/wasm/policy_engine_wasm`, a generated build output imported by
+`wasm-bridge.ts`; it is an expected generated-artifact boundary, not an alias
+failure.
+
+## F-002 — production build has an intentional registry gate
+
+`yarn build:chrome` requires `REGISTRY_BASE_URL` and production signing
+configuration.  The baseline used the explicitly non-distributable local smoke
+mode `DAMBI_ALLOW_INSECURE_REGISTRY=1`; no placeholder production value was
+introduced.  The normal baseline build also generated the WASM artifact.
+
+## F-003 — current WASM exceeds the stated 1.5 MB gzip budget
+
+The generated `policy_engine_wasm_bg.wasm` is 8,057,968 bytes raw and 2,495,488
+bytes gzip.  That is 995,488 bytes (about 66.4%) above a 1,500,000-byte gzip
+budget.  This is a measurement and an approval decision for Phase 3, not a
+request to optimize or alter the engine in Phase 0.
+
+## F-004 — two different security invariants use the label N2
+
+The signature verifier's N2 pins the verification algorithm and public key.
+The declarative engine's N2 warn-closes an empty multicall.  They have distinct
+scope and were documented separately in `docs/security-invariants.md` so a
+mechanical move cannot accidentally conflate them.
+
+## F-005 — pre-existing user worktree change preserved
+
+`browser-extension/default-bundles/day1-safety/package.json` was already
+modified before Phase 0.  It was not changed, staged, or used as a migration
+edit.
+
+## F-006 — private policy-ir dependency includes executable code
+
+The existing graph shows that `policy-store/render.ts:4-5` imports the runtime
+functions `blocksToEst` and `fillParams`, in addition to its IR/store types.
+`policy-store/resolve.ts:10` also imports executable `isEffectiveOn` and
+`missingRequiredHoles` through the types barrel; their definitions are at
+`sdk/policy-store-types.ts:169` and `:176`.
+
+Moving only shared types into core does not remove core's runtime edge to the
+planned private policy-ir package.  The current IR graph has no reverse edge
+to core/backend.  Reversing type ownership without addressing these functions
+would leave dependencies in both directions.  Publishing policy-ir, inlining
+it at build time (including declaration files), or changing the rendering
+boundary requires an explicit decision.  No such change has been implemented.
+
+There is also an existing authoring-WASM dependency:
+`policy-store/render.ts:6` calls `wasm-bridge.estToPolicyText`.  The planned
+runtime/authoring WASM split must account for this path; moving TypeScript
+types alone does not isolate the runtime WASM artifact.