Improve boot readiness retries and normalized diagnostics

[thymikee]

Summary

• add reusable Deadline + policy-driven retry helper in src/utils/retry.ts while keeping withRetry API compatibility
• add shared boot failure classifier with normalized reason codes in src/platforms/boot-diagnostics.ts
• migrate Android boot wait to deadline-aware retries with structured diagnostics and fast-fail behavior for tool/permission issues
• strengthen iOS simulator boot flow with retry + richer boot/bootstatus diagnostics
• add unit tests for retry/deadline and boot diagnostics classification
• include src/utils/**/tests in test:unit so retry utility tests run in standard unit CI

Correctness notes

• Android retry classification now considers command stderr/stdout from error details, not just top-level message
• Android boot path preserves non-timeout root causes instead of always re-wrapping as timeout
• boot failures expose normalized details.reason for CI analysis

Refs #39

[github-actions]

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