feat: safely shut down target disk simulators before eject

[fengfe1125]

Summary

• Eject preflight now inspects Apple simulator devices and verifies whether their data or runtime is stored on the target disk or a related mounted image.
• After confirmation, it requests normal shutdown for each related running device and waits for an explicit shutdown state before detaching images or ejecting the disk.
• Unknown inventory or scope, shutdown errors/timeouts, target changes, and newly started devices stop the flow. System-only and force-eject paths cannot bypass the simulator check.
• Added bilingual progress/failure copy, demo fixtures, flow tests, and documentation.

Verification

• swift test --disable-sandbox --scratch-path /private/tmp/devdisk-swift-build — 222 passed, 3 optional skips.
• git diff --check passed; demo UI snapshot and debug app self-test passed.
• No real disk eject was attempted.

Environment limits

• CoreSimulatorService was unavailable, so live simulator shutdown integration could not be run. The WidgetRenderer_Default crash report showed a SIGTRAP in Apple SimulatorTrampoline/libdispatch; a causal link to DevDisk has not been established.
• Release dSYM generation stopped with Operation not permitted; release packaging and installation were not verified.

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