feat: add test for multiple overrides config files

[jonesho]

This PR implements #456

---

Note

Add multi-file config support to the CLI, introduce a closeable lifecycle interface and factory abstraction, and update tests accordingly.

• CLI:
  • Enhance --config to accept multiple files via comma-separated values or repeated options; update help text and parsing (split=",", arity="1..*").
  • Default network handling preserved; add mixinStandardHelpOptions.
  • Use injected MaruAppFactoryCreator instead of constructing MaruAppFactory directly.
  • On shutdown, call app.stop() then app.close(); remove dryRun and related checks.
• Lifecycle/Interfaces:
  • Introduce LongRunningCloseable (LongRunningService + AutoCloseable).
  • Make MaruApp implement LongRunningCloseable; mark start/stop as overrides.
• Factory:
  • Extract MaruAppFactoryCreator interface; MaruAppFactory.create(...) now satisfies it and returns LongRunningCloseable.
• Tests:
  • Overhaul MaruAppCliTest to use temp files and a fake MaruAppFactoryCreator.
  • Add coverage for multiple config files (both comma-separated and repeated) with override semantics; adjust existing tests to new paths and behaviors.

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 76.19048% with 5 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@6dce8bb). Learn more about missing BASE report.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
app/src/main/kotlin/maru/app/MaruAppCli.kt	82.35%	2 Missing and 1 partial ⚠️
app/src/main/kotlin/maru/app/MaruApp.kt	0.00%	1 Missing ⚠️
app/src/main/kotlin/maru/app/MaruAppFactory.kt	66.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #457   +/-   ##
=======================================
  Coverage        ?   83.25%           
  Complexity      ?     1111           
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  Files           ?      226           
  Lines           ?     8003           
  Branches        ?      624           
=======================================
  Hits            ?     6663           
  Misses          ?     1001           
  Partials        ?      339           

Flag	Coverage Δ
kotlin	83.25% <76.19%> (?)

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