fix: ship clients/web/static so the MCP Apps sandbox proxy loads

`clients/web/static/sandbox_proxy.html` is a committed source file, not a
build artifact, and it was never listed in the root package.json "files"
allowlist. `sandbox-controller.ts` reads it at runtime as
`<runner dir>/../static/sandbox_proxy.html`, so it resolved fine in-repo but
was absent from every published tarball — the read threw and the controller
served its "Sandbox not loaded" fallback page, breaking the Apps tab for
anyone running `npx @modelcontextprotocol/inspector`.

v1 shipped the equivalent as `server/static` in both the root and the server
workspace "files" lists; that entry has no counterpart in v2.

Add `clients/web/static` to the allowlist, and assert it in pack:verify twice
over — once in the tarball packlist and once on disk after install, since what
the runtime needs is the path *relative to* clients/web/build rather than mere
presence in the tarball.

No .npmignore change is needed: clients/web/.gitignore does not list `static`,
so the nested-gitignore packlist hazard that hid `build/` does not apply here.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XAR2Nr9kXbrywFNUVoTe9F

README.md

@@ -278,6 +278,7 @@ The root `package.json` `"files"` allowlist is the source of truth for the tarba
 
 - **No source maps.** The client bundlers set `sourcemap: false` (`clients/{cli,tui}/tsup.config.ts`, `clients/web/tsup.runner.config.ts`); Vite and the launcher's `tsc` already emit none. Maps are ~half the unpacked size and aren't needed at runtime — debug via `npm run dev` on the source.
 - **`clients/web/build` ships via `clients/web/.npmignore`.** `clients/web/.gitignore` lists `build/`, and npm's packlist honors that nested `.gitignore` over the root `"files"` allowlist — so the prod web-server runner was silently missing from the tarball while `clients/web/dist` slipped through (its `.gitignore` only lists `dist-ssr`). `clients/web/.npmignore` overrides the `.gitignore` for publishing so both `build/` (runner) and `dist/` (SPA) ship. The other clients don't need this — none ship a nested `.gitignore`.
+- **`clients/web/static` ships the MCP Apps sandbox proxy.** `clients/web/static/sandbox_proxy.html` is a committed source file (not a build artifact), read from disk at runtime by `clients/web/server/sandbox-controller.ts` as `<runner dir>/../static/sandbox_proxy.html`. It was missing from the root `"files"` allowlist entirely, so every published build failed the Apps tab with **"Sandbox not loaded"** ([#1859](https://github.com/modelcontextprotocol/inspector/issues/1859)) while working fine in the repo. Because the path is resolved *relative to* `clients/web/build`, the directory must ship at that exact location — `pack:verify` asserts both the tarball entry and the installed-on-disk path.
 - **A single version number, read from the root `package.json`.** The Inspector ships as one package with one version, so only the **root** `package.json` carries a `version` — the four `clients/*/package.json`s deliberately have none. Every Node client (CLI, TUI, and the web backend) resolves the version through the shared `readInspectorVersion()` reader in `core/node/version.ts`, which walks up to the root manifest (always present in the tarball). No client `package.json` is read at runtime, so none needs to ship. The web **browser** can't read the filesystem; it gets its version from the backend via `GET /api/config` (see [#1639](https://github.com/modelcontextprotocol/inspector/issues/1639)).
 
 ### `npm run pack:verify` — publish smoke against the real tarball

package.json

@@ -24,6 +24,7 @@
     "clients/launcher/build",
     "clients/web/build",
     "clients/web/dist",
+    "clients/web/static",
     "clients/cli/build",
     "clients/tui/build",
     "scripts/install-clients.mjs"

scripts/pack-and-verify.mjs

@@ -22,8 +22,8 @@
  *
  *   1. builds every client (`npm run build`);
  *   2. packs the publishable tarball (`npm pack`) and inspects its file list —
- *      asserting NO source maps ship and that `clients/web/{build,dist}` are
- *      both present (the two packaging fixes this work landed);
+ *      asserting NO source maps ship and that `clients/web/{build,dist,static}`
+ *      are all present (the packaging fixes this work landed);
  *   3. installs that tarball into a fresh temp dir (real `npm install <tgz>`,
  *      which runs the package's `postinstall`);
  *   4. runs the installed `mcp-inspector` bin: `--help`, `--cli`/`--tui` help
@@ -164,26 +164,31 @@ if (maps.length > 0) {
 }
 
 // 2b. Runtime files that are easy to omit from the packlist and only fail once
-//     installed: both web artifacts — the prod server runner (build) AND the SPA
-//     (dist). `clients/web/build` was previously dropped by the nested
-//     .gitignore. (The version the CLI/TUI report is read from the root
-//     package.json — always shipped — via readInspectorVersion(), so no client
-//     package.json needs to ship; that read is exercised by driving the bin in
-//     step 4.)
+//     installed: the web artifacts — the prod server runner (build), the SPA
+//     (dist), and the MCP Apps sandbox proxy page (static). `clients/web/build`
+//     was previously dropped by the nested .gitignore; `clients/web/static` was
+//     never listed in the root "files" allowlist at all, so the Apps tab failed
+//     with "Sandbox not loaded" on every published build (#1859). None of these
+//     are checked-in-tree failures — only an installed tarball reveals them.
+//     (The version the CLI/TUI report is read from the root package.json —
+//     always shipped — via readInspectorVersion(), so no client package.json
+//     needs to ship; that read is exercised by driving the bin in step 4.)
 for (const required of [
   "clients/web/build/index.js",
   "clients/web/dist/index.html",
+  "clients/web/static/sandbox_proxy.html",
 ]) {
   if (!tarredPaths.includes(required)) {
     fail(
       `expected \`${required}\` in the published tarball but it is missing — ` +
-        `check the "files" field in clients/web/package.json`,
+        `check the "files" field in the root package.json (and that ` +
+        `clients/web/.npmignore does not exclude it)`,
     );
   }
 }
 console.log(
   `pack:verify — tarball OK: ${tarredPaths.length} files, no source maps, ` +
-    `clients/web/{build,dist} present (${(packInfo.unpackedSize / 1048576).toFixed(2)} MB unpacked)`,
+    `clients/web/{build,dist,static} present (${(packInfo.unpackedSize / 1048576).toFixed(2)} MB unpacked)`,
 );
 
 // ---------------------------------------------------------------------------
@@ -229,10 +234,14 @@ try {
   if (!existsSync(bin)) {
     fail(`installed \`mcp-inspector\` bin not found at ${bin}`);
   }
-  // Confirm the two packaging fixes survived install onto disk.
+  // Confirm the packaging fixes survived install onto disk. The sandbox proxy
+  // is resolved at runtime as `<build>/../static/sandbox_proxy.html`, so its
+  // position *relative to* clients/web/build is what matters, not just presence
+  // in the tarball (#1859).
   for (const required of [
     join(installedPkg, "clients", "web", "build", "index.js"),
     join(installedPkg, "clients", "web", "dist", "index.html"),
+    join(installedPkg, "clients", "web", "static", "sandbox_proxy.html"),
     join(installedPkg, "clients", "launcher", "build", "index.js"),
   ]) {
     if (!existsSync(required)) {