stop assuming bunx is on the service's PATH

`Executable not found in $PATH: "bunx"` — installing music died there, after the
clone and after apt had installed ffmpeg. My bug, one commit old: the schema step
spawned `bunx drizzle-kit`.

PM2 starts the platform with a PATH that has `bun` and not `bunx`. That is a
perfectly normal way for a service to be started — a symlink into /usr/local/bin
for the runtime and nothing else — and an install has no business depending on
which of a runtime's shims someone happened to link.

So neither name is looked up now. `process.execPath` is the interpreter already
running this code, so it cannot be missing, and drizzle-kit is invoked by path
through `node_modules/.bin/drizzle-kit` rather than by resolution. A missing CLI
there is reported as "run bun install" instead of as a PATH mystery.

Verified the way the claim demands: re-ran the schema push under
`env -i PATH=/usr/bin:/bin`, where `Bun.which('bunx')` and `Bun.which('bun')` both
return nothing. It works. The previous run proved nothing, because bunx was still
there.

Worth noting for the next spawn added to this path: `git`, `pm2` and `sudo` are
still PATH lookups, and they are the ones that were already working on the
machines we have. Anything new should follow this pattern instead.

tsgo clean, frontend builds, 873 pass / 7 fail unchanged.

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

src/servers/plugins/schema.ts

@@ -127,7 +127,21 @@ export default defineConfig({
     writeFileSync(configPath, config);
 
     // `generate`, never `push`. See the note above this function.
-    const generated = await runLogged(['bunx', 'drizzle-kit', 'generate', `--config=${basename(configPath)}`], {
+    //
+    // Invoked through THIS process's own bun and drizzle-kit's bin symlink, never through `bunx`. A
+    // member's install failed with `Executable not found in $PATH: "bunx"` — the platform runs under PM2
+    // with a PATH that has `bun` and not `bunx`, which is a normal way for a service to be started and
+    // not something an install should depend on. `process.execPath` is the interpreter already running,
+    // so it cannot be missing, and `node_modules/.bin/drizzle-kit` is a path rather than a lookup.
+    const cli = join(PLATFORM_DIR, 'node_modules/.bin/drizzle-kit');
+    if (!existsSync(cli)) {
+      return {
+        ok: false,
+        ms: Date.now() - started,
+        output: `drizzle-kit is not installed at ${cli} — run \`bun install\` in the platform directory`,
+      };
+    }
+    const generated = await runLogged([process.execPath, cli, 'generate', `--config=${basename(configPath)}`], {
       cwd: dbDir,
       onLog,
     });