fix: add n8n 1.121 availableInMCP and callerPolicy settings support (v2.26.4) (#445)

* fix: add n8n 1.121 availableInMCP and callerPolicy settings support (v2.26.4)

n8n 1.121 introduced a new workflow setting `availableInMCP` (boolean)
that controls whether a workflow is "Available in MCP". The sanitization
whitelist was missing this field, causing it to be silently stripped
during workflow updates.

Changes:
- Added `availableInMCP` to Zod schema in workflowSettingsSchema
- Added `availableInMCP` and `callerPolicy` to safeSettingsProperties whitelist
- Both settings are now preserved during workflow updates
- Settings can be toggled via updateSettings operation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
Conceived by Romuald Członkowski - www.aiadvisors.pl/en

* test: update tests for callerPolicy and availableInMCP whitelist changes

Updated 5 tests in n8n-validation.test.ts that expected callerPolicy
to be filtered out. Since callerPolicy and availableInMCP are now
whitelisted (n8n 1.121+), the tests now verify these settings are
preserved during workflow updates.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

---------

Co-authored-by: Claude <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.26.3",
+  "version": "2.26.4",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",