feat: add patchNodeField operation for surgical string edits (v2.46.0) (#698)

Add dedicated `patchNodeField` operation to `n8n_update_partial_workflow`
for surgical find/replace edits in node string fields. Strict alternative
to the existing `__patch_find_replace` in updateNode — errors on not-found,
detects ambiguous matches, supports replaceAll and regex flags.

Security hardening:
- Prototype pollution protection in setNestedProperty/getNestedProperty
- ReDoS protection rejecting unsafe regex patterns (nested quantifiers)
- Resource limits: max 50 patches, 500-char regex, 512KB field size

Fixes #696

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.runtime.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.45.1",
+  "version": "2.46.0",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {