Update Zig version in .devcontainer/Dockerfile

[hulto]

Updated the ZIG_VERSION in .devcontainer/Dockerfile to the latest master version 0.16.0-dev.2915+065c6e794 as per the official Zig download index. Verified the change and ran project tests to ensure stability.

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PR created automatically by Jules for task 229620823261477020 started by @hulto

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[github-actions]

Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
2833    ±0	2833    ±0	0    ±0	0    ±0	0    ±0	0    ±0	1ms    ±0

Previous Results

Build 🏗️	Result 🧪	Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
#1813	✅	2833	2833	0	0	0	0	37.8s

Insights

Average Tests per Run	Total Flaky Tests	Total Failed	Slowest Test (p95)
2833	0	0	5.7s

Slowest Tests

Test 📝	Results 📊	Duration (avg) ⏱️	Duration (p95) ⏱️
TestDockerExecutor_Build_ContextCancellation	1	5.7s	5.7s
eldritch-libsys: std::dll_inject_impl::tests::test_dll_inject_simple	1	5.1s	5.1s
TestInteractiveShell	1	5.1s	5.1s
TestOtherStreamOutput	1	5.0s	5.0s
imix::bin/imix: install::tests::test_install_execution	3	1.8s	4.9s
imix::bin/imix: install::tests::test_install_execution	3	1.8s	4.9s
imix::bin/imix: install::tests::test_install_execution	3	1.8s	4.9s
imix::bin/imix: tests::task_tests::test_task_streaming_error	3	3.0s	3.0s
imix::bin/imix: tests::task_tests::test_task_streaming_error	3	3.0s	3.0s
imix::bin/imix: tests::task_tests::test_task_streaming_error	3	3.0s	3.0s

_{🎉 No failed tests in this run. | 🍂 No flaky tests in this run.}

Github Test Reporter by CTRF 💚