ci: pin pi-studio to newest semver tag, not main HEAD

Upstream omaclaren/pi-studio stopped publishing GitHub Releases at v0.5.55
but keeps tagging every version (v0.9.36 now) and pushing to main. Tracking
main HEAD risked baking half-finished commits that land after a tag.

resolve-versions now lists all tags via a single git ls-remote (the REST
tags API paginates at 100 and the repo has >140 tags, so a single page can
miss the newest), picks the highest X.Y.Z with sort -V (pre-releases
excluded), and peels it to a commit SHA for PI_STUDIO_REF. SHA (not moving
tag) keeps cache-busting + reproducibility; require_sha still enforced.

Studio-variant only, not base-affecting. No change to the resolved commit
today (v0.9.36 == current main HEAD). Validated: yq parse OK, bash -n OK,
live git ls-remote -> v0.9.36 -> 2ef38ef. No tag.

.gitea/workflows/docker-publish.yml

@@ -199,16 +199,39 @@ jobs:
           require_sha MEMPALACE_TOOLKIT_REF "$MEMPALACE_TOOLKIT_REF"
           echo "mempalace_toolkit_ref=${MEMPALACE_TOOLKIT_REF}" >> "$GITHUB_OUTPUT"
 
-          # pi-studio (omaclaren/pi-studio) → commit SHA for :latest-studio.
-          STUDIO_REF=$(curl -sf -H "Accept: application/vnd.github.sha" \
-            "https://api.github.com/repos/omaclaren/pi-studio/commits/main" || true)
+          # pi-studio (omaclaren/pi-studio) → newest SEMVER TAG's commit SHA
+          # for the :*-studio images. Upstream stopped publishing GitHub
+          # *Releases* at v0.5.55 but keeps tagging every version (vX.Y.Z) and
+          # pushing to main, so pinning main HEAD risked baking half-finished
+          # commits that land after a tag. Take the newest stable tag instead.
+          # List ALL tags in one `git ls-remote` call — the REST tags API
+          # paginates at 100 and this repo already has >140 tags, so page 1 is
+          # NOT guaranteed to hold the newest — pick the highest X.Y.Z with
+          # `sort -V` (pre-releases like -rc1 excluded by the strict filter),
+          # then resolve its commit SHA (a SHA, not a moving tag, preserves
+          # cache-busting + reproducibility and is what require_sha demands).
+          STUDIO_TAGS=$(git ls-remote --tags "https://github.com/omaclaren/pi-studio.git" || true)
+          STUDIO_TAG=$(printf '%s\n' "$STUDIO_TAGS" | awk '{print $2}' \
+            | sed -n 's#^refs/tags/##p' \
+            | grep -E '^v?[0-9]+\.[0-9]+\.[0-9]+$' \
+            | sort -V | tail -n1 || true)
+          if [ -z "${STUDIO_TAG:-}" ]; then
+            echo "::error::Could not resolve a pi-studio semver tag (git ls-remote empty/unreachable). Refusing to fall back to a floating ref."
+            exit 1
+          fi
+          # Prefer the peeled ^{} line (annotated tags); fall back to the
+          # direct ref (lightweight tags, which pi-studio currently uses).
+          STUDIO_REF=$(printf '%s\n' "$STUDIO_TAGS" | awk -v t="refs/tags/${STUDIO_TAG}^{}" '$2==t{print $1}')
+          if [ -z "$STUDIO_REF" ]; then
+            STUDIO_REF=$(printf '%s\n' "$STUDIO_TAGS" | awk -v t="refs/tags/${STUDIO_TAG}" '$2==t{print $1}')
+          fi
           require_sha PI_STUDIO_REF "$STUDIO_REF"
           echo "studio_ref=${STUDIO_REF}" >> "$GITHUB_OUTPUT"
 
           echo "Resolved PI_VERSION=${PI_VERSION}"
           echo "Resolved PI_FORK_REF=${FORK_REF}, PI_OBSMEM_REF=${OBSMEM_REF}"
           echo "Resolved PI_TOOLKIT_REF=${TOOLKIT_REF}, PI_EXTENSIONS_REF=${EXTENSIONS_REF}"
-          echo "Resolved PI_STUDIO_REF=${STUDIO_REF}"
+          echo "Resolved PI_STUDIO_REF=${STUDIO_REF} (pi-studio ${STUDIO_TAG})"
           echo "Resolved MEMPALACE_TOOLKIT_REF=${MEMPALACE_TOOLKIT_REF}"
 
   # ── Phase 2: build & push base (multi-arch), only when needed ──────

CHANGELOG.md

@@ -33,6 +33,22 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
   overridden per-user (`:set notermguicolors`, or your own init). Base-affecting
   (`Dockerfile.base` apt package + COPY), rebuilds `base-<hash>`.
 
+### Changed
+
+- **`-studio` images now pin pi-studio to its newest *semver tag* instead of
+  `main` HEAD.** Upstream `omaclaren/pi-studio` abandoned GitHub *Releases* at
+  v0.5.55 but keeps tagging every version (currently `v0.9.36`) and pushing to
+  `main`; tracking `main` HEAD risked baking half-finished commits that land
+  after a tag. CI (`resolve-versions`) now lists every tag via a single
+  `git ls-remote` (the REST tags API paginates at 100 and the repo already has
+  >140 tags), selects the highest `X.Y.Z` with `sort -V` (pre-releases
+  excluded by a strict filter), and pins that tag's commit SHA into
+  `PI_STUDIO_REF`. Pinning the SHA (not the moving tag) preserves cache-busting
+  and reproducibility, is what `require_sha` demands, and is recorded in the
+  `se.jordbo.pi-devbox.pi-studio-ref` image label. Studio-variant only — not
+  base-affecting; takes effect on the next `-studio` build. No change to the
+  resolved commit today (`v0.9.36` == current `main` HEAD).
+
 ### Fixed
 
 - **`pandoc --pdf-engine=typst` now works without `-V mainfont`.** pandoc's