refactor(agents): move tools package to app/agents/shared (slice 6)

Relocate the entire new_chat/tools/ package (62 files incl. registry, hitl, MCP
cluster, and all connector subpackages: gmail/slack/discord/teams/drive/etc.)
to the shared kernel. The package turned out to be a clean cohesive cluster:
its only references to non-tools new_chat modules were comments, and its
middleware deps were already flipped to shared in slice 5c.

Flip 33 live importers (multi-agent, flows, routes, services, anonymous_agent,
tests). Re-export shims remain for the frozen single-agent stack: a package
__init__ mirroring the public surface (new_chat.__init__ imports it) plus
invalid_tool + registry submodule shims (chat_deepagent imports those).

Resolves slice 5c's two transient back-edges: shared/middleware/action_log
(TYPE_CHECKING ToolDefinition) and tool_call_repair (local INVALID_TOOL_NAME)
now point at app.agents.shared.tools.

surfsense_backend/tests/e2e/fakes/native_google.py

@@ -429,9 +429,9 @@ def install(active_patches: list[Any]) -> None:
         ("app.connectors.google_drive.client.build", _fake_build),
         ("app.connectors.google_gmail_connector.build", _fake_build),
         ("app.connectors.google_calendar_connector.build", _fake_build),
-        ("app.agents.new_chat.tools.google_calendar.create_event.build", _fake_build),
-        ("app.agents.new_chat.tools.google_calendar.update_event.build", _fake_build),
-        ("app.agents.new_chat.tools.google_calendar.delete_event.build", _fake_build),
+        ("app.agents.shared.tools.google_calendar.create_event.build", _fake_build),
+        ("app.agents.shared.tools.google_calendar.update_event.build", _fake_build),
+        ("app.agents.shared.tools.google_calendar.delete_event.build", _fake_build),
         ("googleapiclient.http.MediaIoBaseDownload", _FakeMediaIoBaseDownload),
         (
             "app.connectors.google_drive.client._build_thread_http",