fix(c++): use std::move to reduce a copy

[SYaoJun]

Reason for this PR

I found a potential improvemnt spot in status.h. issue: #842

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[Copilot]

Pull request overview

This PR targets small C++ performance cleanups in Status construction in GraphAr’s C++ runtime, aligning with issue #842’s goal of reducing unnecessary string copies in status.h.

Changes:

• Change Status(StatusCode, const std::string&) to take std::string by value and move into internal storage.
• Simplify Status::OK() to return {}.
• Adjust Status::FromArgs(...) to move the StringBuilder(...) result into the constructor.

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[Copilot]

std::move on the temporary returned by util::StringBuilder(...) is counterproductive here: it forces materialization of the temporary and can inhibit copy elision into the by-value Status constructor parameter, potentially adding an extra move (and for SSO strings, possibly a copy). Passing the return value directly should be at least as efficient and keeps the intent clearer.

Suggested change

	return Status(code, std::move(util::StringBuilder(std::forward<Args>(args)...)));
	return Status(code, util::StringBuilder(std::forward<Args>(args)...));

[Copilot]

FromArgs takes its parameter pack by value (Args... args), which defeats the perfect-forwarding used by IOError/KeyError/... and can introduce extra copies of the formatting arguments. Consider changing it to Args&&... args and forwarding those into util::StringBuilder to preserve the callers’ value categories.

Suggested change

	static Status FromArgs(StatusCode code, Args... args) {
	static Status FromArgs(StatusCode code, Args&&... args) {

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.21%. Comparing base (7bad8ec) to head (770d4d2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #843   +/-   ##
=========================================
  Coverage     80.21%   80.21%           
  Complexity      615      615           
=========================================
  Files            93       93           
  Lines         10265    10265           
  Branches       1047     1049    +2     
=========================================
  Hits           8234     8234           
  Misses         1791     1791           
  Partials        240      240           

Flag	Coverage Δ
cpp	71.52% <100.00%> (ø)

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[SYaoJun]

@yangxk1y could you please review my code

[yangxk1]

LGTM~