chore(deps): update pnpm to v9.15.9 (#2215)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

apps/agentstack-sdk-ts/package.json

@@ -99,5 +99,5 @@
     "typescript": "5.9.3",
     "vitest": "3.2.4"
   },
-  "packageManager": "pnpm@9.9.0"
+  "packageManager": "pnpm@9.15.9"
 }

apps/agentstack-ui/package.json

@@ -90,5 +90,5 @@
     "stylelint": "catalog:",
     "typescript": "catalog:"
   },
-  "packageManager": "pnpm@9.9.0"
+  "packageManager": "pnpm@9.15.9"
 }

apps/beeai-web/package.json

@@ -41,5 +41,5 @@
     "stylelint": "catalog:",
     "typescript": "catalog:"
   },
-  "packageManager": "pnpm@9.9.0"
+  "packageManager": "pnpm@9.15.9"
 }

docs/package.json

@@ -10,7 +10,7 @@
   "keywords": [],
   "author": "IBM Corp.",
   "license": "ISC",
-  "packageManager": "pnpm@9.9.0",
+  "packageManager": "pnpm@9.15.9",
   "devDependencies": {
     "@i-am-bee/lint-config": "workspace:*",
     "embedme": "1.22.1",