fix(dashboard): use pattern match for .env sensitive file guard

Replace the exact-filename frozenset with _is_sensitive_filename()
that matches .env plus any .env.<suffix> variant.  This covers
shorthand suffixes like .env.prod that the previous enumeration
missed.

Add test_sensitive_env_suffix_variants_blocked regression test
covering .env.prod, .env.dev, .env.staging.local, and .env.ci.

Addresses review feedback from egilewski on PR #57507.

hermes_cli/web_server.py

@@ -1191,15 +1191,9 @@ _FS_READDIR_HIDDEN = {
 # managed-files API.  These typically contain credentials (API keys, tokens)
 # and exposing them through the dashboard file browser is a security leak —
 # see issue #57505.
-_SENSITIVE_FILENAMES: frozenset[str] = frozenset({
-    ".env",
-    ".env.local",
-    ".env.production",
-    ".env.development",
-    ".env.staging",
-    ".env.test",
-    ".env.backup",
-})
+def _is_sensitive_filename(name: str) -> bool:
+    """Return True for ``.env`` and any ``.env.<suffix>`` variant."""
+    return name == ".env" or name.startswith(".env.")
 _FS_DATA_URL_MAX_BYTES = 16 * 1024 * 1024
 _FS_TEXT_SOURCE_MAX_BYTES = 64 * 1024 * 1024
 _FS_TEXT_PREVIEW_MAX_BYTES = 512 * 1024
@@ -1633,7 +1627,7 @@ async def list_managed_files(request: Request, path: Optional[str] = None):
         entries = [
             _managed_file_entry(policy, child)
             for child in target.iterdir()
-            if child.name not in _SENSITIVE_FILENAMES
+            if not _is_sensitive_filename(child.name)
         ]
     except PermissionError:
         raise HTTPException(status_code=403, detail="Directory is not readable")
@@ -1660,7 +1654,7 @@ async def read_managed_file(request: Request, path: str):
         raise HTTPException(status_code=404, detail="File not found")
     if not target.is_file():
         raise HTTPException(status_code=400, detail="Path is not a file")
-    if target.name in _SENSITIVE_FILENAMES:
+    if _is_sensitive_filename(target.name):
         raise HTTPException(status_code=403, detail="Access to sensitive files is not allowed")
 
     try:
@@ -1704,7 +1698,7 @@ async def download_managed_file(request: Request, path: str):
         raise HTTPException(status_code=404, detail="File not found")
     if not target.is_file():
         raise HTTPException(status_code=400, detail="Path is not a file")
-    if target.name in _SENSITIVE_FILENAMES:
+    if _is_sensitive_filename(target.name):
         raise HTTPException(status_code=403, detail="Access to sensitive files is not allowed")
 
     try:

tests/hermes_cli/test_web_server_files.py

@@ -494,7 +494,7 @@ def test_sensitive_env_files_hidden_from_listing(forced_files_client):
     """Regression test for #57505: .env files must not appear in directory listings."""
     client, root = forced_files_client
 
-    # Create a regular file and a .env file.
+    # Create a regular file and .env variants including shorthand suffixes.
     root.mkdir(parents=True, exist_ok=True)
     regular = root / "config.txt"
     regular.write_text("safe content")
@@ -502,6 +502,8 @@ def test_sensitive_env_files_hidden_from_listing(forced_files_client):
     env_file.write_text("SECRET_KEY=abc123")
     env_local = root / ".env.local"
     env_local.write_text("LOCAL_SECRET=def456")
+    env_prod = root / ".env.prod"
+    env_prod.write_text("PROD_SECRET=ghi789")
 
     listing = client.get("/api/files", params={"path": str(root)})
     assert listing.status_code == 200
@@ -509,6 +511,7 @@ def test_sensitive_env_files_hidden_from_listing(forced_files_client):
     assert "config.txt" in names
     assert ".env" not in names
     assert ".env.local" not in names
+    assert ".env.prod" not in names
 
 
 def test_sensitive_env_files_blocked_read(forced_files_client):
@@ -533,3 +536,15 @@ def test_sensitive_env_files_blocked_download(forced_files_client):
 
     resp = client.get("/api/files/download", params={"path": str(env_file)})
     assert resp.status_code == 403
+
+
+def test_sensitive_env_suffix_variants_blocked(forced_files_client):
+    """Regression: .env.<suffix> shorthand variants (e.g. .env.prod) must also be blocked."""
+    client, root = forced_files_client
+
+    root.mkdir(parents=True, exist_ok=True)
+    for suffix in ("prod", "dev", "staging.local", "ci"):
+        p = root / f".env.{suffix}"
+        p.write_text(f"SECRET_{suffix}=abc123")
+        assert client.get("/api/files/read", params={"path": str(p)}).status_code == 403
+        assert client.get("/api/files/download", params={"path": str(p)}).status_code == 403