refactor: remove dead image media attachment code

- Remove generated_image_paths_from_messages() and _extract_text_payload() from artifacts.py (no runtime callers)
- Remove session_attachments.py entirely (merge_turn_media_into_last_assistant and stage_media_paths_for_session_replay had no runtime callers)
- Remove test_session_media_persist.py and the orphaned test in test_artifacts.py

nanobot/utils/artifacts.py

@@ -21,8 +21,6 @@ _MIME_EXTENSIONS = {
     "image/webp": ".webp",
     "image/gif": ".gif",
 }
-_GENERATE_IMAGE_TOOL_NAME = "generate_image"
-
 
 class ArtifactError(ValueError):
     """Raised when an artifact cannot be safely decoded or stored."""
@@ -124,40 +122,3 @@ def generated_image_tool_result(artifacts: list[dict[str, Any]]) -> str:
     )
 
 
-def _extract_text_payload(content: Any) -> str | None:
-    if isinstance(content, str):
-        return content
-    if isinstance(content, list):
-        parts: list[str] = []
-        for block in content:
-            if isinstance(block, dict) and isinstance(block.get("text"), str):
-                parts.append(block["text"])
-        return "\n".join(parts) if parts else None
-    return None
-
-
-def generated_image_paths_from_messages(messages: list[dict[str, Any]]) -> list[str]:
-    """Collect generated image artifact paths from generate_image tool results."""
-    paths: list[str] = []
-    seen: set[str] = set()
-    for message in messages:
-        if message.get("role") != "tool" or message.get("name") != _GENERATE_IMAGE_TOOL_NAME:
-            continue
-        payload = _extract_text_payload(message.get("content"))
-        if not payload:
-            continue
-        try:
-            data = json.loads(payload)
-        except json.JSONDecodeError:
-            continue
-        artifacts = data.get("artifacts") if isinstance(data, dict) else None
-        if not isinstance(artifacts, list):
-            continue
-        for artifact in artifacts:
-            if not isinstance(artifact, dict):
-                continue
-            path = artifact.get("path")
-            if isinstance(path, str) and path and path not in seen:
-                paths.append(path)
-                seen.add(path)
-    return paths

nanobot/utils/session_attachments.py

@@ -1,74 +0,0 @@
-"""Session replay: ensure assistant ``media`` paths are under the media root.
-
-WebUI history signing (``/api/.../messages``) only works for files inside
-``get_media_dir``. Tool-driven attachments may live in the workspace; stage
-copies into the websocket media bucket before persisting message JSON.
-"""
-
-from __future__ import annotations
-
-import shutil
-import uuid
-from pathlib import Path
-from typing import Any
-
-from loguru import logger
-
-from nanobot.config.paths import get_media_dir
-from nanobot.utils.helpers import safe_filename
-
-
-def stage_media_paths_for_session_replay(paths: list[str]) -> list[str]:
-    """Keep local files only; copy anything outside the media root into ``media/websocket``."""
-    root = get_media_dir().resolve()
-    out: list[str] = []
-    seen: set[str] = set()
-    for raw in paths:
-        if not isinstance(raw, str) or not raw.strip():
-            continue
-        if raw.startswith(("http://", "https://")):
-            continue
-        try:
-            p = Path(raw).expanduser().resolve()
-        except OSError:
-            continue
-        if not p.is_file():
-            continue
-        try:
-            p.relative_to(root)
-            key = str(p)
-        except ValueError:
-            try:
-                media_dir = get_media_dir("websocket")
-                staged = media_dir / f"{uuid.uuid4().hex[:12]}-{safe_filename(p.name) or 'attachment'}"
-                shutil.copyfile(p, staged)
-                key = str(staged.resolve())
-            except OSError as exc:
-                logger.warning("failed to stage session media from {}: {}", raw, exc)
-                continue
-        if key not in seen:
-            out.append(key)
-            seen.add(key)
-    return out
-
-
-def merge_turn_media_into_last_assistant(
-    all_messages: list[dict[str, Any]],
-    generated_image_paths: list[str],
-    extra_attachment_paths: list[str],
-) -> None:
-    """Attach staged paths to the last assistant row in *all_messages* (in-place)."""
-    merged = list(
-        dict.fromkeys(
-            [
-                *stage_media_paths_for_session_replay(generated_image_paths),
-                *stage_media_paths_for_session_replay(extra_attachment_paths),
-            ]
-        )
-    )
-    last = all_messages[-1] if all_messages else None
-    if not merged or not last or last.get("role") != "assistant":
-        return
-    existing = last.get("media")
-    base = existing if isinstance(existing, list) else []
-    last["media"] = list(dict.fromkeys([*base, *merged]))