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/utils/notes.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import difflib
+import hashlib
 import json
 import os
 from pathlib import Path
@@ -181,6 +182,33 @@ def save_note_content(base_dir: str | Path, key: str, content: str) -> None:
         logger.debug("Failed to publish note_saved event for key '%s': %s", key, exc)
 
 
+def save_verified_note(base_dir: str | Path, key: str, content: str) -> dict:
+    """Task-local text delivery using the shared note store, with a read-back receipt."""
+    if not key.strip(" .") or key != key.strip() or re.search(r'[<>:"/\\|?*\x00-\x1f]', key):
+        raise ValueError("笔记 key 必须是普通名称，不能是路径")
+    root = Path(base_dir).resolve()
+    notes = get_notes_dir(root)
+    path = get_note_file_path(root, key)
+    if (
+        notes.resolve().parent != root
+        or path.is_symlink()
+        or path.resolve().parent != notes.resolve()
+    ):
+        raise ValueError("笔记不能通过链接写入任务目录之外")
+    save_note_content(root, key, content)
+    data = path.read_bytes()
+    # save_note_content uses the platform's text newline conversion.
+    if data != content.replace("\n", os.linesep).encode("utf-8"):
+        raise OSError("笔记写入后读回不一致，不能确认交付")
+    return {
+        "ok": True,
+        "path": path.relative_to(root).as_posix(),
+        "bytes": len(data),
+        "sha256": hashlib.sha256(data).hexdigest(),
+        "verified": True,
+    }
+
+
 def append_note_content(base_dir: str | Path, key: str, content: str) -> None:
     """Appends raw content to a note, inserting a newline if the file is not empty and lacks a trailing newline."""
     notes_dir = get_notes_dir(base_dir)