feat(status): expose mode on /version and GET /authz

[neiljar]

What type of PR is this?

/kind enhancement

What this PR does / why we need it:

Expose daemon dataplane mode on GET /version and add GET /authz returning {"enabled": bool}.

Today dump/BPF callers must guess kernel-native vs dual-engine, and kmeshctl authz status GETs /authz but the status server only allowed POST. This is groundwork for the MCP server (#1800) so tools like get_version, config_dump, and get_authz_status can use structured status APIs.

Which issue(s) this PR fixes:
Related to #1800

Special notes for your reviewer:

• mode is filled from BpfConfig.Mode (default dual-engine); omitted for client-only version info via omitempty
• POST /authz?enable= behavior unchanged

Does this PR introduce a user-facing change?:

status server: /version includes dataplane mode; GET /authz returns authz offload enabled status

[kmesh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign yaozengzeng for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• pkg/OWNERS

Approvers can indicate their approval by writing /approve in a comment
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[codecov]

Codecov Report

❌ Patch coverage is 0% with 19 lines in your changes missing coverage. Please review.
✅ Project coverage is 39.46%. Comparing base (32fe3df) to head (5f5f872).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/status/status_server.go	0.00%	19 Missing ⚠️

❌ Your patch check has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Files with missing lines	Coverage Δ
pkg/version/version.go	0.00% <ø> (ø)
pkg/status/status_server.go	34.05% <0.00%> (-1.76%)	⬇️

... and 1 file with indirect coverage changes

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