feat: add extender support

[TGJLS]

Summary

• Add support for registering Adaptix C2 extenders (listener, agent, listener+agent, BOF) from a git URL
• Parse .axs files with dukpy (Duktape ES5) to extract config schemas and classify fields as auto/generate/network/required
• Store annotated extender profiles in SQLite; manage profile.yaml atomically
• Orchestrate installation via testing-kit-cli add-extender (git clone → install script → activate → docker restart)
• Add test-kharon and test-extension-kit CI jobs

Test plan

• 150 unit tests pass locally (extenders DB, .axs parser, profile_manager, REST API, runner integration)
• unit-tests CI job (pytest on PR)
• integration-test CI job (existing E2E test with new volume mounts + tasks.yaml path)
• test-kharon CI job (end-to-end Kharon extender registration and activation)
• test-extension-kit CI job (Extension-Kit BOF collection)

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