dev-inf: Fix Claude model names in GH action

Changed model names from invalid format (claude-sonnet-4-5-20250929)
to correct Vertex AI format (claude-sonnet-4-5@20250929) with @ symbol.

Epic: none
Release note: none

Author: ajstorm

.github/workflows/pr-analyzer-threestage.yml

@@ -36,7 +36,7 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           use_vertex: "true"
           claude_args: |
-            --model claude-sonnet-4-5-20250929
+            --model claude-sonnet-4-5@20250929
             --allowedTools "Read,Grep,Glob,Bash(gh pr diff:*),Bash(gh pr view:*)"
           track_progress: true
           prompt: |
@@ -74,7 +74,7 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           use_vertex: "true"
           claude_args: |
-            --model claude-4-5-sonnet-20250929
+            --model claude-sonnet-4-5@20250929
             --allowedTools "Read,Grep,Glob,Bash(gh pr diff:*),Bash(gh pr view:*)"
           track_progress: true
           prompt: |
@@ -113,7 +113,7 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           use_vertex: "true"
           claude_args: |
-            --model claude-4-5-sonnet-20250929
+            --model claude-sonnet-4-5@20250929
             --allowedTools "Read,Grep,Glob,Bash(gh pr diff:*),Bash(gh pr view:*)"
           track_progress: true
           prompt: |
@@ -166,7 +166,7 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           use_vertex: "true"
           claude_args: |
-            --model claude-4-5-sonnet-20250929
+            --model claude-sonnet-4-5@20250929
             --allowedTools "Read,Grep,Glob,Bash(gh pr diff:*),Bash(gh pr view:*)"
           prompt: |
             REPO: ${{ github.repository }}