a plugin may not bring its own React

Installing tiptap for fofos-admin took the whole plugin screen down: "Cannot
read properties of null (reading 'useRef')", both panels, nothing rendering.

Two Reacts. The platform has 19.2.4; `@tiptap/react` declares React as a PEER,
bun installs peers, and 19.2.8 landed in plugins/node_modules where it wins
resolution for everything underneath. React holds its hook dispatcher in module
state, so a second instance is not a duplicated dependency — it is a broken one,
and the error names nothing that would lead anybody here.

Easy to reach by accident, since nobody asks for React. It arrives underneath
something that does.

So platform-owned packages are stripped from the merged list AND deleted after
the install, and the second is the one that does the work: no plugin declares
React, so there is nothing in the list to strip. Deleting afterwards is crude and
deterministic, which is the right trade for a failure whose symptom is every
panel on a screen refusing to render.

Stripped rather than pinned. Matching the platform's version would still be two
copies, and two copies is the entire problem — bun resolves up the tree, so
removing them is what makes a plugin use the one already loaded.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/servers/plugins/npm-deps.ts

@@ -1,3 +1,4 @@
+import { existsSync, rmSync } from 'node:fs';
 import { join } from 'node:path';
 import { PLATFORM_DIR } from '../data-path';
 import type { DiscoveredPlugin } from './manifest';
@@ -104,6 +105,32 @@ export async function installNpmDependencies(plugins: DiscoveredPlugin[]): Promi
     return { ok: true, ran: false, output: '', conflicts };
   }
 
+  /*
+  Packages the PLATFORM owns, which a plugin may never bring its own copy of.
+
+  React holds module-level state — the hook dispatcher — so two copies in one page is not a duplicated
+  dependency, it is a broken one. The second instance's `useRef` reads a null dispatcher and every panel
+  fails to render with "Cannot read properties of null (reading 'useRef')", which names nothing that
+  would lead somebody here.
+
+  It is easy to arrive at by accident and hard to diagnose: nobody asks for React. `@tiptap/react`
+  declares it as a PEER, bun installs peers, and the copy lands in plugins/node_modules where it wins
+  resolution for everything under it. That took the fofos-admin screen down the moment tiptap arrived.
+
+  Stripped rather than pinned. Matching the platform's version would still be two copies, and two copies
+  is the whole problem — bun resolves up the tree, so removing them entirely is what makes a plugin use
+  the one the platform already loaded.
+
+  Removed AFTER the install as well as before it, and the second is the one that does the work: no
+  plugin declares React, so there is nothing to strip from the merged list. It arrives as a PEER of
+  something that does, which bun installs and the generated file never mentions.
+*/
+const PLATFORM_OWNED = ['react', 'react-dom'];
+
+  for (const owned of PLATFORM_OWNED) {
+    if (owned in merged) delete merged[owned];
+  }
+
 const body = {
     name: '@officer/plugin-dependencies',
     private: true,
@@ -117,7 +144,26 @@ export async function installNpmDependencies(plugins: DiscoveredPlugin[]): Promi
     const proc = Bun.spawn(['bun', 'install'], { cwd: PLUGINS_DIR, stdout: 'pipe', stderr: 'pipe' });
     const [out, err] = await Promise.all([new Response(proc.stdout).text(), new Response(proc.stderr).text()]);
     const code = await proc.exited;
-    return { ok: code === 0, ran: true, output: `${out}${err}`.trim(), conflicts };
+
+    /*
+      Evict the platform's singletons, however they got here.
+
+      This is the step that matters. Stripping the merged list above only covers a plugin ASKING for
+      React, and none do — it arrives as a peer of something that does, so bun installs it without the
+      generated file ever naming it. Deleting it afterwards is crude and it is deterministic, which is
+      the right trade for a failure whose symptom is every panel on a screen refusing to render.
+    */
+    const evicted: string[] = [];
+    for (const owned of PLATFORM_OWNED) {
+      const path = join(PLUGINS_DIR, 'node_modules', owned);
+      if (existsSync(path)) {
+        rmSync(path, { recursive: true, force: true });
+        evicted.push(owned);
+      }
+    }
+
+    const note = evicted.length ? `\nremoved ${evicted.join(', ')} — the platform owns those` : '';
+    return { ok: code === 0, ran: true, output: `${out}${err}${note}`.trim(), conflicts };
   } catch (error) {
     return { ok: false, ran: true, output: error instanceof Error ? error.message : String(error), conflicts };
   }