test: separate manual e2e tests and add one-to-one unit test structure

[0xWelt]

Changes

Test Structure

• Move all manual e2e tests from testing/ops/ and testing/ui/*/e2e.py to testing/manual/
• Update imports and sys.path for manual tests
• Add norecursedirs = ['manual'] and --import-mode=importlib to pytest config

One-to-One Unit Tests

• Create 108 test files mirroring the autowsgr source layout
• Add missing __init__.py for namespace packages

Real Unit Tests for Core Modules

• context/: build, equipment, expedition, fleet, game_context, resources, ship
• scheduler/: launcher, scheduler
• server/: main, schemas, serializers
• infra/logger: 8 cases with mock
• types.py: enum and model tests

Bug Fix

• Fix save_image() creating a literal None/ directory when img_dir is None

Verification

• pytest: 539 passed
• pre-commit: all clean

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