feat(workspace): add shared workspace plan

bot_bottle/workspace.py

@@ -0,0 +1,52 @@
+"""Backend-neutral plan for porting the operator workspace."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Protocol
+
+
+WORKSPACE_DIRNAME = "workspace"
+DEFAULT_WORKSPACE_OWNER = "node:node"
+DEFAULT_WORKSPACE_MODE = "755"
+
+
+class WorkspaceSpec(Protocol):
+    copy_cwd: bool
+    user_cwd: str
+
+
+@dataclass(frozen=True)
+class WorkspacePlan:
+    """Resolved workspace contract shared by all bottle backends."""
+
+    enabled: bool
+    host_path: Path
+    guest_home: str
+    guest_path: str
+    workdir: str
+    owner: str = DEFAULT_WORKSPACE_OWNER
+    mode: str = DEFAULT_WORKSPACE_MODE
+    copy_contents: bool = True
+    copy_git: bool = True
+    has_host_git_dir: bool = False
+
+
+def workspace_plan(spec: WorkspaceSpec, *, guest_home: str) -> WorkspacePlan:
+    """Resolve the in-bottle workspace path from CLI intent."""
+    host_path = Path(spec.user_cwd).expanduser()
+    if spec.copy_cwd:
+        guest_path = f"{guest_home.rstrip('/')}/{WORKSPACE_DIRNAME}"
+        workdir = guest_path
+    else:
+        guest_path = guest_home
+        workdir = guest_home
+    return WorkspacePlan(
+        enabled=spec.copy_cwd,
+        host_path=host_path,
+        guest_home=guest_home,
+        guest_path=guest_path,
+        workdir=workdir,
+        has_host_git_dir=(host_path / ".git").is_dir(),
+    )