effect(bootstrap): pin Effect deps, register ESLint plugin, dedupe

Pins effect@^3.21.2 and @effect/platform@^0.96.1 as runtime deps in
@arcp/core, @arcp/runtime, @arcp/client, @arcp/sdk. Adds
@effect/eslint-plugin@^0.3.2 to root devDeps and registers it in
eslint.config.js without enabling any rules — individual slices opt
files in as they migrate.

@effect/opentelemetry@^0.63.0 is added as a peer of @arcp/middleware-otel
(used in slice #49).

@effect/vitest is intentionally NOT pinned: the latest stable (0.29.0)
requires vitest@^3.2.0 while this workspace is on vitest@^2.1.2.
Slices use plain `it()` with `Effect.runPromise(...)` until a separate
vitest 2->3 upgrade is opened.

.gitignore picks up .effect-migration/, where the migration's scratch
issue bodies and orchestration script live (see issue #20).

Quality gates: pnpm lint, pnpm typecheck, and all 103 tests pass.

Closes #31

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Nick Ficano

.gitignore

@@ -9,3 +9,4 @@ coverage/
 *.tsbuildinfo
 .vitest/
 *.tgz
+.effect-migration/

eslint.config.js

@@ -1,3 +1,4 @@
+import effect from "@effect/eslint-plugin";
 import eslint from "@eslint/js";
 import prettier from "eslint-config-prettier";
 import importPlugin from "eslint-plugin-import";
@@ -24,6 +25,10 @@ export default tseslint.config(
   importPlugin.flatConfigs.recommended,
   importPlugin.flatConfigs.typescript,
   n.configs["flat/recommended-module"],
+  // @effect/eslint-plugin — registered, no rules enabled at root.
+  // Effect-specific rules (e.g. dangling-effects, no-import-from-barrel)
+  // get opted in by individual files as the migration progresses.
+  { plugins: { effect } },
   {
     languageOptions: {
       parserOptions: {

package.json

@@ -38,6 +38,7 @@
   "devDependencies": {
     "@arethetypeswrong/cli": "^0.18.2",
     "@biomejs/biome": "^2.4.15",
+    "@effect/eslint-plugin": "^0.3.2",
     "@eslint/js": "^9.39.4",
     "@types/node": "^22.7.5",
     "@vitest/coverage-v8": "^2.1.2",

packages/client/package.json

@@ -43,6 +43,8 @@
   },
   "dependencies": {
     "@arcp/core": "workspace:*",
+    "@effect/platform": "^0.96.1",
+    "effect": "^3.21.2",
     "zod": "^3.23.8"
   },
   "devDependencies": {

packages/core/package.json

@@ -90,7 +90,9 @@
     "test:coverage": "vitest run --coverage"
   },
   "dependencies": {
+    "@effect/platform": "^0.96.1",
     "better-sqlite3": "^11.5.0",
+    "effect": "^3.21.2",
     "jose": "^5.9.6",
     "pino": "^9.5.0",
     "ulid": "^2.3.0",

packages/middleware/otel/package.json

@@ -43,10 +43,12 @@
   },
   "peerDependencies": {
     "@arcp/core": "workspace:^",
+    "@effect/opentelemetry": "^0.63.0",
     "@opentelemetry/api": "^1.9.0"
   },
   "devDependencies": {
     "@arcp/core": "workspace:*",
+    "@effect/opentelemetry": "^0.63.0",
     "@opentelemetry/api": "^1.9.0",
     "@types/node": "^22.7.5",
     "typescript": "^5.6.2",

packages/runtime/package.json

@@ -43,6 +43,8 @@
   },
   "dependencies": {
     "@arcp/core": "workspace:*",
+    "@effect/platform": "^0.96.1",
+    "effect": "^3.21.2",
     "zod": "^3.23.8"
   },
   "devDependencies": {

packages/sdk/package.json

@@ -70,7 +70,9 @@
     "@arcp/client": "workspace:*",
     "@arcp/core": "workspace:*",
     "@arcp/runtime": "workspace:*",
-    "commander": "^12.1.0"
+    "@effect/platform": "^0.96.1",
+    "commander": "^12.1.0",
+    "effect": "^3.21.2"
   },
   "devDependencies": {
     "@types/node": "^22.7.5",