cli(feat[privacy]): Contract home paths in JSON/NDJSON output

why: Fix inconsistency where workspace_root used ~/ but path showed full
/home/username/ paths, exposing usernames and reducing portability
what:
- Apply contract_user_home() to path field in list.py (flat and tree views)
- Apply contract_user_home() to path field in status.py (status dict)
- Apply contract_user_home() to path field in sync.py (PlanEntry and events)
- All JSON/NDJSON output now consistently uses ~/... notation
- Human output already used tilde notation (unchanged)

Before:
  {"path": "/home/username/code/flask", "workspace_root": "~/code/"}

After:
  {"path": "~/code/flask", "workspace_root": "~/code/"}

Benefits:
- Consistency: Both path and workspace_root now use tilde
- Privacy: No username exposure in JSON dumps
- Portability: Configs/output work across different machines
- Matches shell conventions and user expectations

refs: Breaking change - automation may need to expand ~ to absolute paths

Author: tony

src/vcspull/cli/list.py

@@ -161,12 +161,12 @@ def _output_flat(
         repo_url = repo.get("url", repo.get("pip_url", "unknown"))
         repo_path = repo.get("path", "unknown")
 
-        # JSON/NDJSON output
+        # JSON/NDJSON output (contract home for privacy/portability)
         formatter.emit(
             {
                 "name": repo_name,
                 "url": str(repo_url),
-                "path": str(repo_path),
+                "path": contract_user_home(repo_path),
                 "workspace_root": str(repo.get("workspace_root", "")),
             }
         )
@@ -212,12 +212,12 @@ def _output_tree(
             repo_url = repo.get("url", repo.get("pip_url", "unknown"))
             repo_path = repo.get("path", "unknown")
 
-            # JSON/NDJSON output
+            # JSON/NDJSON output (contract home for privacy/portability)
             formatter.emit(
                 {
                     "name": repo_name,
                     "url": str(repo_url),
-                    "path": str(repo_path),
+                    "path": contract_user_home(repo_path),
                     "workspace_root": workspace,
                 }
             )

src/vcspull/cli/status.py

@@ -263,7 +263,7 @@ def check_repo_status(repo: ConfigDict, detailed: bool = False) -> dict[str, t.A
 
     status: dict[str, t.Any] = {
         "name": repo_name,
-        "path": str(repo_path),
+        "path": contract_user_home(repo_path),
         "workspace_root": workspace_root,
         "exists": False,
         "is_git": False,

src/vcspull/cli/sync.py

@@ -264,7 +264,7 @@ def _build_plan_entry(
 
     return PlanEntry(
         name=str(repo.get("name", "unknown")),
-        path=str(repo_path),
+        path=contract_user_home(repo_path),
         workspace_root=workspace_root,
         action=action,
         detail=detail,
@@ -724,7 +724,7 @@ def silent_progress(output: str, timestamp: datetime) -> None:
         event: dict[str, t.Any] = {
             "reason": "sync",
             "name": repo_name,
-            "path": str(repo_path),
+            "path": contract_user_home(repo_path),
             "workspace_root": str(workspace_label),
         }