refactor: simplify build flags and update command-line options in main.go

[kazeburo]

PR Type

Enhancement

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Description

• Adopt flagrun for standardized CLI execution

• Delegate plugin startup through Opt.Run

• Simplify build metadata to version only

• Document generated help output

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Diagram Walkthrough

flowchart LR
  Main["main function"]
  Flagrun["flagrun Ship"]
  Options["Opt Run handler"]
  Plugin["Mackerel memory plugin"]
  Main -- "starts" --> Flagrun
  Flagrun -- "invokes" --> Options
  Options -- "runs" --> Plugin

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File Walkthrough

	Relevant files
Enhancement	main.go Use flagrun for CLI lifecycle handling                                      main.go Replace manual go-flags parsing with flagrun.Ship Move plugin execution into Opt.Run Delegate version and help handling to flagrun Remove commit, runtime, and executable metadata output +6/-30
Configuration changes	Makefile Simplify build metadata linker flags                                          Makefile Stop embedding the Git commit in linker flags Retain version injection through main.version Correct and expand .PHONY targets +2/-3
Documentation	README.md Document generated command-line help output                            README.md Replace version-output example with CLI usage output Document version and help command-line options +8/-3
Dependencies	go.mod Add flagrun command-line dependency                                            go.mod Add the github.com/monitoring-forge/flagrun dependency Reclassify go-flags as an indirect dependency Add indirect dependencies required by flagrun +6/-1

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

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🔒 No security concerns identified

⚡ No major issues detected

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