ci: pin Xcode 26.6, build for iOS, stop tracking Package.resolved

.github/workflows/ci.yml

@@ -1,9 +1,10 @@
-# DiffractoKit CI: the gate (`swift test -c release`), the consumer check, the README consumer and the example.
+# DiffractoKit CI: the gate (`swift test -c release`), the consumer check, the README consumer, the example and an iOS
+# Simulator build.
 #
-# The package's floor is macOS 15 / iOS 18 (since 0.2.0) with tools 6.2; `macos-latest`
-# is used with the newest Xcode on the image selected. On 2026-10-15 that was Xcode 26.6, whose compiler (not the local Swift
-# 6.4) crashed in its SIL ownership verifier on `catch SomeError.someCase { ... }` clauses in the tests (run 38747583963): the
-# tests therefore bind the error (`catch let caught as SomeError`) and match the case in the body.
+# The package's floor is macOS 15 / iOS 18 (since 0.2.0) with tools 6.2; the macos-26 image with Xcode 26.6 is pinned below.
+# Xcode 26.6's compiler crashed in its SIL ownership verifier on `catch SomeError.someCase { ... }` clauses in the tests
+# (run 38747583963, 2026-10-15): the tests therefore bind the error (`catch let caught as SomeError`) and match the case in
+# the body. Package.resolved is not tracked, so CI resolves the newest ImagoKit the manifest's range allows, as a consumer does.
 #
 # THE PINS' PYTHON ORACLES ARE NOT RUN HERE. The tests read committed fixtures (Tests/*/Fixtures/*.json, generated by
 # tools/*/pins.py against pymatgen 2026.9.24, pymatgen-core 2026.9.23, spglib 2.8.0, NumPy 2.5.4, SciPy 1.18.1 and py4DSTEM
@@ -25,16 +26,19 @@ concurrency:
   group: ci-${{ github.ref }}
   cancel-in-progress: true
 
+env:
+  # Pinned like the apps: the macos-26 image's Xcode 26.6 (Swift 6.3, macOS 26 SDK). Bump on purpose.
+  DEVELOPER_DIR: /Applications/Xcode_26.6.app/Contents/Developer
+
 jobs:
   test:
-    runs-on: macos-latest
+    runs-on: macos-26
     timeout-minutes: 90
     steps:
       - uses: actions/checkout@v7
-      - name: Select the newest Xcode
+      - name: Toolchain on record
         run: |
-          xcode=$(ls -d /Applications/Xcode*.app | sort -V | tail -1)
-          sudo xcode-select -s "$xcode"
+          xcode-select -p
           swift --version
       - name: Gate (swift test, release)
         run: swift test -c release
@@ -47,6 +51,17 @@ jobs:
           swift build -c release --product diffracto-example
           "$(swift build -c release --show-bin-path)/diffracto-example"
 
+  post-merge:
+    name: iOS build (after merge)
+    # Not on pull requests: the free plan's macOS runners are scarce, so the extra builds run on main, tags and by hand.
+    if: github.event_name != 'pull_request'
+    runs-on: macos-26
+    timeout-minutes: 90
+    steps:
+      - uses: actions/checkout@v7
+      - name: Build the libraries for iOS (Simulator, not run)
+        run: xcodebuild -scheme DiffractoKit-Package -destination 'generic/platform=iOS Simulator' -quiet build
+
   version:
     name: CHANGELOG version matches the tag
     runs-on: ubuntu-latest
@@ -74,7 +89,7 @@ jobs:
     name: Lint (shared SwiftLint and SwiftFormat config)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - name: SwiftLint
         run: docker run --rm -v "$PWD:/work" -w /work --entrypoint swiftlint ghcr.io/realm/swiftlint:0.65.1 lint --strict --quiet
       - name: SwiftFormat

.github/workflows/docs.yml

@@ -2,7 +2,7 @@
 # published to GitHub Pages at https://mac4dstem.github.io/DiffractoKit/documentation/ on every tag.
 # On a pull request the site is built and uploaded as an artifact only, so a broken catalog fails before the tag.
 #
-# No swift-docc-plugin: the kit takes no package dependencies. `xcodebuild docbuild` builds the archives
+# No swift-docc-plugin: the kit adds no dependency for its docs (its one package dependency is ImagoKit). `xcodebuild docbuild` builds the archives
 # from the package's own schemes; `docc merge` (Xcode 16+) joins them. Needs Pages enabled with source "GitHub Actions"
 # (repository Settings > Pages). Copied from CuboKit's pattern; the module list is read from the .docc catalogs.
 name: Docs
@@ -23,16 +23,19 @@ concurrency:
   group: docs-${{ github.ref }}
   cancel-in-progress: true
 
+env:
+  # Pinned like the apps: the macos-26 image's Xcode 26.6 (Swift 6.3, macOS 26 SDK). Bump on purpose.
+  DEVELOPER_DIR: /Applications/Xcode_26.6.app/Contents/Developer
+
 jobs:
   build:
-    runs-on: macos-latest
+    runs-on: macos-26
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v7
-      - name: Select the newest Xcode
+      - name: Toolchain on record
         run: |
-          xcode=$(ls -d /Applications/Xcode*.app | sort -V | tail -1)
-          sudo xcode-select -s "$xcode"
+          xcode-select -p
           xcodebuild -version
       - name: Build the site
         run: tools/build-docs.sh .docs-site /DiffractoKit

.gitignore

@@ -10,3 +10,4 @@ tools/benchmarks/.build/
 # Local session rules, kept on disk only
 CLAUDE.md
 .claude/
+/Package.resolved