refactor: organize API routers and services into subpackages

Service organization (19 files moved into 6 subpackages):
- services/instance/ — event_bus, health_monitor, lifecycle_hooks
- services/config/ — config_profile_resolver
- services/git/ — clone, git_operations, git_service
- services/build/ — docker_build, manifest_compiler
- services/terminal/ — terminal_manager, terminal_session
- services/shared/ — correlation, file_service, notification_service,
  permission_fixer, readiness_probe, ssh_keys, tunnel, workspace_manager

API router organization (16 files moved into 6 subpackages):
- api/tool/ — tool_instances, tool_types, tool_definitions,
  tool_types_validation, sessions (extracted from tool_instances)
- api/config/ — config_profiles, user_config
- api/workspace/ — workspaces, workspace_files, workspace_git,
  workspace_instances
- api/user/ — users, auth, ssh_keys
- api/project/ — projects, git_repositories
- api/system/ — health, events, notifications, dashboard, terminal,
  instance_proxy

Updated main.py imports and all __init__.py re-exports.
Sessions router extracted from tool_instances.py into api/tool/sessions.py.

Quality gates: py_compile passed, ruff passed.

apps/api/src/services/config/__init__.py

@@ -1 +1,25 @@
-"""Config module."""
+"""Config profile services module."""
+
+from src.services.config.config_profile_resolver import (
+    ConfigProfileCycleError,
+    ConfigProfileNotFoundError,
+    ResolvedMount,
+    ResolvedProfile,
+    apply_resolved_profile,
+    check_include_cycle,
+    expand_container_path,
+    resolve_profile,
+    resolved_profile_to_dict,
+)
+
+__all__ = [
+    "ConfigProfileCycleError",
+    "ConfigProfileNotFoundError",
+    "ResolvedMount",
+    "ResolvedProfile",
+    "apply_resolved_profile",
+    "check_include_cycle",
+    "expand_container_path",
+    "resolve_profile",
+    "resolved_profile_to_dict",
+]