Deno lts-2.9

Apply the JavaScript ES2026 prompt first. These rules cover the Deno 2.9 LTS line, its Node/npm compatibility, HTTP services, storage, compiled programs, and experimental desktop applications, and were checked against the LTS-channel 2.9.3 build. The stable 2.9.3 build has the same source version but a different embedded channel marker; do not assume fixes from later 2.9 patches are present in 2.9.3.

LTS identity and patch boundaries

• Verify the version, lts channel, and target reported by deno --version, and preserve the verified artifact and checksum through images, caches, deployment, and rollback.
• Run the newest build on the Deno 2.9 LTS channel and redeploy when Deno ships a new one. deno upgrade lts installs it, and no version number selects an LTS build: deno upgrade 2.9.3 installs the stable build instead. Preserve an approved artifact when reproducing 2.9.3. The lts-2.9 in this prompt's title names the LTS line these rules cover; they were checked against its 2.9.3 build, and neither number names a build to install.
• Deno publishes no container image tag that follows the LTS channel, so install the runtime in the image with deno upgrade lts or from a reviewed LTS artifact and its checksum, and check that deno --version in the built image reports long term support. In GitHub Actions, denoland/setup-deno with deno-version: lts follows the channel. When a Dockerfile, .dvmrc, .tool-versions, or CI matrix needs an exact version you can't check against the LTS channel, leave a placeholder that fails the build, such as an ARG DENO_VERSION