test(snapshot): follow persona prefix config

snapshots/acp/image-offload/cordis.snapshot.yml

@@ -27,7 +27,7 @@
 - id: system-prompt
   name: '@deepseek-ai/dsh-system-prompt'
   config:
-    persona: |
+    personaPrefix: |
       You are a coding assistant powered by the {{model}} model. Your working directory is {{cwd}}. Your bash tool runs under a file sandbox — a `[sandbox: file access denied …]` result is policy, not a command bug.
 
       Verify your work by running the code or tests. Keep answers brief and factual.

snapshots/acp/image-offload/cordis.yml

@@ -24,7 +24,7 @@
 - id: system-prompt
   name: '@deepseek-ai/dsh-system-prompt'
   config:
-    persona: |
+    personaPrefix: |
       You are a coding assistant powered by the {{model}} model. Your working directory is {{cwd}}. Your bash tool runs under a file sandbox — a `[sandbox: file access denied …]` result is policy, not a command bug.
 
       Verify your work by running the code or tests. Keep answers brief and factual.

snapshots/sdk/inline-image-prompt/cordis.snapshot.yml

@@ -13,7 +13,7 @@
 - id: system-prompt
   name: '@deepseek-ai/dsh-system-prompt'
   config:
-    persona: |
+    personaPrefix: |
       You are a coding assistant powered by the {{model}} model. Your working directory is {{cwd}}. Your bash tool runs under a file sandbox — a `[sandbox: file access denied …]` result is policy, not a command bug.
 
       Verify your work by running the code or tests. Keep answers brief and factual.

snapshots/sdk/inline-image-prompt/cordis.yml

@@ -9,7 +9,7 @@
 - id: system-prompt
   name: '@deepseek-ai/dsh-system-prompt'
   config:
-    persona: |
+    personaPrefix: |
       You are a coding assistant powered by the {{model}} model. Your working directory is {{cwd}}. Your bash tool runs under a file sandbox — a `[sandbox: file access denied …]` result is policy, not a command bug.
 
       Verify your work by running the code or tests. Keep answers brief and factual.