style: fix ruff check — drop unused re-exports, retarget imports

Ruff autofix removed unused re-exports from http_common.py. The three
security helpers (validate_host_header, enforce_same_origin_write,
resolve_allowed_origin) were re-exported there for backward-compat but
genuinely not used by http_common itself. Retargeted the two callers
(http_standalone.py, http_standalone_endpoints.py) to import straight
from http_security where the real implementations live.

All 17 F401 issues resolved. Lint + format + 1657 tests green.

Author: cdeust

mcp_server/core/workflow_graph_schema.py

@@ -27,21 +27,6 @@
 
 # Re-export enums + palette so existing callers (handlers, builder,
 # tests) keep importing from ``workflow_graph_schema`` unchanged.
-from mcp_server.core.workflow_graph_palette import (
-    AGENT_COLOR,
-    COMMAND_COLOR,
-    DISCUSSION_COLOR,
-    DOMAIN_COLOR,
-    ENTITY_COLOR,
-    HOOK_COLOR,
-    MCP_COLOR,
-    MEMORY_STAGE_COLORS,
-    PRIMARY_TOOL_COLORS,
-    SKILL_COLOR,
-    TOOL_HUB_COLORS,
-    classify_primary_tool,
-    primary_tool_color,
-)
 from mcp_server.core.workflow_graph_schema_enums import (
     EdgeKind,
     NodeKind,

mcp_server/server/http_common.py

@@ -40,9 +40,6 @@
 # backward-compatibility with existing import sites.
 from mcp_server.server.http_security import (  # noqa: E402
     _apply_cors_headers,
-    enforce_same_origin_write,
-    resolve_allowed_origin,
-    validate_host_header,
 )
 
 

mcp_server/server/http_file_diff.py

@@ -33,8 +33,6 @@ def serve_file_diff(handler) -> None:
         handler.end_headers()
         return
 
-    from pathlib import Path
-
     from mcp_server.infrastructure.git_diff import (
         find_git_root,
         get_file_diff,

mcp_server/server/http_standalone.py

@@ -28,8 +28,8 @@
 from pathlib import Path
 from socketserver import ThreadingMixIn
 
-from mcp_server.server.http_common import (
-    _apply_cors_headers,
+from mcp_server.server.http_common import _apply_cors_headers
+from mcp_server.server.http_security import (
     enforce_same_origin_write,
     validate_host_header,
 )

mcp_server/server/http_standalone_endpoints.py

@@ -19,7 +19,8 @@
 from http.server import BaseHTTPRequestHandler
 from pathlib import Path
 
-from mcp_server.server.http_common import _apply_cors_headers, validate_host_header
+from mcp_server.server.http_common import _apply_cors_headers
+from mcp_server.server.http_security import validate_host_header
 from mcp_server.server.http_standalone_graph import (
     build_discussion_detail,
     build_discussions_response,