feat: add official Codex skill and harden task execution

Install and update artemis-use with task diagnostics and plugin guidance. Preserve cross-device file receipts, review canonical reports, guard stage transitions and reduce small history summaries. Improve exploration lifecycle, request recovery and browser live connections.

artemis/config/agent.py

@@ -643,7 +643,7 @@ class MemoryChunkingConfig(BaseModel):
         ),
     )
     target_source_tokens: int = Field(
-        default=2000,
+        default=6000,
         ge=128,
         description=(
             "Size-threshold trigger: estimated source tokens (transcript"
@@ -653,7 +653,7 @@ class MemoryChunkingConfig(BaseModel):
         ),
     )
     min_steps: int = Field(
-        default=3,
+        default=6,
         ge=1,
         description=(
             "Minimum turns in a chunk closed by the size or pressure trigger:"