feat(deno): migrate flat-mate workspace → deno.json (3/4 manifests; apps/mobile Class C deferred, standards#253 longtail) (#16)

Workspace-style migration covering 3 of 4 npm manifests. The fourth
(`apps/mobile/package.json`) is Class C — Expo / React Native /
Metro bundler ecosystem cannot run under Deno, so the npm manifest
remains as a host-required carve-out (parallel to the VSCode-extension
class).

## Migrated

- **`/deno.json`** (was root `package.json`) — Deno workspace with
  `apps/web` + `packages/shared` members, plus `tasks` for `dev:api`
  (Deno-native), `dev:web` (delegates to apps/web workspace), and
  `check` (deno check + lint + node --check → deno check). `dev:mobile`
  task emits a Class C documentation message instead of orchestrating.
- **`apps/web/deno.json`** (was `apps/web/package.json`) — Class B
  with `imports` for react/react-dom/vite/@vitejs/plugin-react via
  `npm:` specifiers; tasks via `deno run -A --node-modules-dir=auto
  npm:vite@^8.0.7 …`.
- **`packages/shared/deno.json`** (was `packages/shared/package.json`)
  — Class A; pure JS barrel-export package with no scripts, just
  `name` + `version` + `license` + `exports`.

## Deferred (Class C)

- **`apps/mobile/package.json`** — Expo SDK + React Native + Metro
  bundler require Node + npm/yarn/pnpm. Deno cannot run `expo start`,
  Metro is fundamentally npm-rooted. Same Class C pattern as VSCode
  extensions (host requires npm). Tracked as Class C carve-out
  candidate for hypatia rule extension (per-repo follow-up).

## Test plan

- [ ] `deno task dev:api` runs the Deno-native API server (unchanged)
- [ ] `deno task dev:web` chains to apps/web deno task dev (vite)
- [ ] `deno task check` validates apps/api + packages/shared
- [ ] apps/mobile still works with npm (unchanged)

Per per-repo follow-up tracker for standards#253 (campaign closed
2026-05-31, longtail tracked in project_estate_npm_to_deno_2026_05_28.md).

Refs hyperpolymath/standards#253.

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

Author: hyperpolymath

apps/web/deno.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://deno.land/x/deno/cli/schemas/config-file.v1.json",
+  "name": "@flat-mate/web",
+  "version": "0.1.0",
+  "license": "MPL-2.0",
+  "tasks": {
+    "dev": "deno run -A --node-modules-dir=auto npm:vite@^8.0.7",
+    "build": "deno run -A --node-modules-dir=auto npm:vite@^8.0.7 build",
+    "preview": "deno run -A --node-modules-dir=auto npm:vite@^8.0.7 preview"
+  },
+  "imports": {
+    "react": "npm:react@^18.3.1",
+    "react-dom": "npm:react-dom@^18.3.1",
+    "@vitejs/plugin-react": "npm:@vitejs/plugin-react@^4.4.1",
+    "vite": "npm:vite@^8.0.7"
+  },
+  "nodeModulesDir": "auto"
+}

apps/web/package.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "https://deno.land/x/deno/cli/schemas/config-file.v1.json",
+  "name": "@hyperpolymath/flat-mate",
+  "version": "0.1.0",
+  "license": "MPL-2.0",
+  "workspace": [
+    "./apps/web",
+    "./packages/shared"
+  ],
+  "tasks": {
+    "dev:api": "deno run --watch=apps/api --allow-net --allow-env apps/api/main.ts",
+    "dev:web": "deno task --cwd apps/web dev",
+    "dev:mobile": "echo 'apps/mobile is an Expo project; run `cd apps/mobile && npm install && npm run start` (Expo CLI requires Node — see Class C carve-out in README)'",
+    "build:web": "deno task --cwd apps/web build",
+    "check": "deno check apps/api/main.ts && deno lint apps/api && deno check packages/shared/src/domain.js"
+  },
+  "fmt": {
+    "useTabs": false,
+    "lineWidth": 100,
+    "indentWidth": 2,
+    "singleQuote": false
+  },
+  "lint": {
+    "rules": {
+      "tags": ["recommended"]
+    }
+  }
+}

deno.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "https://deno.land/x/deno/cli/schemas/config-file.v1.json",
+  "name": "@flat-mate/shared",
+  "version": "0.1.0",
+  "license": "MPL-2.0",
+  "exports": "./src/index.js"
+}