Release TeX Live 2026.1 as the default image (#36382)

* feat: releasing 2026.1 texlive to general release and promoting to default image

* fix: update clsi image tests so their likeness calcs work locally on different archs

* feat: updating epstopdf fixture and adding note to texlive Dockerfile used for codespaces

* fix: use generated image-eps-convert instead of fixture version that drifts

GitOrigin-RevId: 13c4f6977dbf07ddd34c9a5ab3ea295cddcbe025

services/clsi/README.md

@@ -28,7 +28,7 @@ The CLSI can be configured through the following environment variables:
 - `LISTEN_ADDRESS` - The address for the RESTful service to listen on. Set to `0.0.0.0` to listen on all network interfaces
 - `PROCESS_LIFE_SPAN_LIMIT_MS` - Process life span limit in milliseconds
 - `SMOKE_TEST` - Whether to run smoke tests
-- `TEXLIVE_IMAGE` - The TeX Live Docker image to use for sibling containers, e.g. `us-east1-docker.pkg.dev/overleaf-ops/ol-docker/texlive-full:2025.1`
+- `TEXLIVE_IMAGE` - The TeX Live Docker image to use for sibling containers, e.g. `us-east1-docker.pkg.dev/overleaf-ops/ol-docker/texlive-full:2026.1`
 - `TEX_LIVE_IMAGE_NAME_OVERRIDE` - The name of the registry for the Docker image e.g. `us-east1-docker.pkg.dev/overleaf-ops/ol-docker`
 - `TEXLIVE_IMAGE_USER` - When using sibling containers, the user to run as in the TeX Live image. Defaults to `tex`
 - `TEXLIVE_OPENOUT_ANY` - Sets the `openout_any` environment variable for TeX Live (see the `\openout` primitive [documentation](http://tug.org/texinfohtml/web2c.html#tex-invocation))

services/clsi/test/acceptance/js/ExampleDocumentTests.js

@@ -41,6 +41,13 @@ const convertToPng = function (pdfPath, pngPath) {
   })
 }
 
+// ImageMagick reports the mean absolute error as "<absolute> (<normalised>)".
+// Identical images do not always yield an exact zero: aarch64 builds leave
+// floating point residue behind, so comparing an image against a byte-identical
+// copy of itself measures around 2e-20. A single differing pixel measures around
+// 7e-07, so anything below this threshold is the same image.
+const MAX_NORMALISED_MAE = 1e-12
+
 const compare = function (originalPath, generatedPath) {
   return new Promise((resolve, reject) => {
     const diffFile = `${fixturePath(generatedPath)}-diff.png`
@@ -52,7 +59,12 @@ const compare = function (originalPath, generatedPath) {
     let stderr = ''
     proc.stderr.on('data', chunk => (stderr += chunk))
     proc.on('exit', () => {
-      if (stderr.trim() === '0 (0)') {
+      // take the parenthesised value: "1.55242e-15 (2.36884e-20)" -> "2.36884e-20".
+      // a failed comparison (mismatched dimensions, missing file) does not match
+      // the metric format, leaving NaN, which fails the threshold check below
+      const match = stderr.trim().match(/\((?<normalised>[^)]+)\)$/)
+      const normalisedMae = match ? parseFloat(match.groups.normalised) : NaN
+      if (normalisedMae <= MAX_NORMALISED_MAE) {
         // remove output diff if test matches expected image
         fs.unlink(diffFile, err => {
           if (err) {