feat(validator): detect conditional branch fan-out & connection auto-fixes (#622)

* feat(auto-fixer): add 5 connection structure fix types

Add automatic repair for malformed workflow connections commonly
generated by AI models:
- connection-numeric-keys: "0","1" keys → main[0], main[1]
- connection-invalid-type: type:"0" → type:"main" (or parent key)
- connection-id-to-name: node ID refs → node name refs
- connection-duplicate-removal: dedup identical connection entries
- connection-input-index: out-of-bounds input index → clamped

Includes collision-safe ID-to-name renames, medium confidence on
merge conflicts and index clamping, shared CONNECTION_FIX_TYPES
constant, and 24 unit tests.

Concieved by Romuald Członkowski - www.aiadvisors.pl/en


* feat(validator): detect IF/Switch/Filter conditional branch fan-out misuse

Add CONDITIONAL_BRANCH_FANOUT warning when conditional nodes have all
connections on main[0] with higher outputs empty, indicating both
branches execute together instead of being split by condition.

Extract getShortNodeType() and getConditionalOutputInfo() helpers to
deduplicate conditional node detection logic.

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

dist/services/workflow-validator.d.ts

@@ -1,5 +1,6 @@
 import { NodeRepository } from '../database/node-repository';
 import { EnhancedConfigValidator } from './enhanced-config-validator';
+export declare const VALID_CONNECTION_TYPES: Set<string>;
 interface WorkflowNode {
     id: string;
     name: string;
@@ -84,7 +85,12 @@ export declare class WorkflowValidator {
     private validateErrorOutputConfiguration;
     private validateAIToolConnection;
     private validateAIToolSource;
+    private getNodeOutputTypes;
+    private validateNotAISubNode;
+    private getShortNodeType;
+    private getConditionalOutputInfo;
     private validateOutputIndexBounds;
+    private validateConditionalBranchUsage;
     private validateInputIndexBounds;
     private flagOrphanedNodes;
     private validateTriggerReachability;