diff --git a/.dockerignore b/.dockerignore
index 938a46c7..0ab4ab54 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -6,9 +6,20 @@
 **/build
 web/build
 
-# Flutter mobile client — built separately on developer machines / Flutter CI.
-# Including it in the Go build context wastes ~70 files and invalidates the
-# `COPY . .` layer cache on every Flutter-only change.
+# The Android client — built by its own job, never from this context. The APK
+# reaches the image through client/, downloaded as a CI artifact, so nothing
+# here reads android/ sources.
+#
+# This block named `flutter_client/` until 2026-09-10 and lost its PATTERN when
+# that tree was deleted, leaving a comment describing an exclusion that was no
+# longer happening. android/ never took its place, so 4.1 MB of Gradle project
+# has been entering the context and busting the `COPY . .` layer on every
+# Android-only change.
+android/
+
+# Local `make build` output — an 18 MB binary the image never uses, since the
+# builder stage compiles its own.
+bin/
 
 # Docs and IDE noise
 docs/
@@ -26,5 +37,8 @@ docs/
 !.env.example
 
 # CI workflow files don't need to ship in the image.
-.forgejo/
-.github/
+#
+# This said `.forgejo/` and `.github/` — neither of which this repo has. Gitea
+# Actions reads `.gitea/`, so the one directory that actually exists was the
+# one not excluded, and every workflow edit invalidated the context.
+.gitea/
diff --git a/.gitignore b/.gitignore
index f1619185..11b676e2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,11 @@
 # Test binary, built with `go test -c`
 *.test
 
+# `make build` output. bin/minstrel was tracked until 2026-09-10 — an 18 MB
+# binary committed by accident, last refreshed by a commit about web test
+# mocks, and re-dirtied by every local build since.
+bin/
+
 # Bundled Android APK + version sidecar (#397). Populated by CI for
 # tag releases; never committed. README in client/ explains the flow.
 client/minstrel.apk
diff --git a/bin/minstrel b/bin/minstrel
deleted file mode 100755
index 9b34c685..00000000
Binary files a/bin/minstrel and /dev/null differ
diff --git a/ci/version.sh b/ci/version.sh
index 72d115df..fb8774ef 100755
--- a/ci/version.sh
+++ b/ci/version.sh
@@ -2,7 +2,8 @@
 #
 # Derives the three values a build is stamped with, and the tag that names it.
 #
-#   name=YYYY.MM.DD.HHMM   label for people, from the COMMIT's timestamp
+#   name=YYYY.MM.DD.HHMM   label for people, from the timestamp of the newest
+#                          commit that CHANGED SOMETHING SHIPPED (see SHIPPED)
 #   code=<int>             ordering key, minutes since 2020-01-01 at BUILD time
 #   tag=v<name>            what a release of this commit must be called
 #
@@ -33,9 +34,61 @@ readonly REF="${1:-HEAD}"
 
 # Both clocks are overridable so a test can pin them. Nothing but tests should
 # set these — the defaults are the real derivation.
+# The paths that do NOT ship, in either artifact. Everything else counts.
+#
+# A DENYLIST, and the direction is the whole point. As an allowlist, the list
+# has to be updated by whoever adds a directory and nothing fails if they
+# don't — so the failure mode is a changed artifact keeping its old version,
+# silently, on a green run. That is a build lying about what it is. Inverted,
+# new content counts by default and the only way to wrongly EXCLUDE something
+# is to name it here deliberately.
+#
+# The two error directions are not symmetric, which is why this is not taste:
+#   wrongly excluded → changed artifact, unchanged version. A silent lie.
+#   wrongly included → version moves when nothing shipped. Cosmetic noise in
+#                      a string nobody sorts.
+#
+# THIS REPO SHIPS TWO ARTIFACTS FROM ONE DERIVATION, and that is why the list
+# is shorter than it looks like it should be. The server image ships cmd/,
+# internal/, shared/, web/, config.example.yaml and client/; the APK ships
+# android/. Neither ships the other's sources — but excluding android/ here
+# would stop an Android-only commit from moving the APK's OWN version, which
+# is the dangerous direction. So this is the union: exclude only what ships in
+# NEITHER, and accept that an Android commit also nudges the server's reported
+# version. Over-inclusion across the two, which is the harmless direction.
+#
+# The family's other repos (roundtable / roundtable-android) each keep a
+# tighter list because they are separate repos with one artifact apiece. Do
+# not copy theirs onto this one.
+readonly SHIPPED=(
+  .
+  ':!.gitea'          # CI workflows — including this script's own caller
+  ':!ci'              # CI scripts — including this script
+  ':!docs'
+  ':!tools'           # asset/font generators; their OUTPUT ships, they do not
+  ':!deploy'          # test-database bootstrap SQL
+  ':!bin'             # local `make build` output
+  ':!*.md'
+  ':!Makefile'
+  ':!docker-compose.yml'
+  ':!.env.example'
+  ':!.gitignore'
+  ':!.dockerignore'
+  ':!renovate.json'
+  ':!.golangci.yml'
+)
+
 commit_epoch="${MINSTREL_COMMIT_EPOCH:-}"
 if [ -z "${commit_epoch}" ]; then
-  commit_epoch="$(git log --format=%ct -1 "${REF}")"
+  commit_epoch="$(git log --format=%ct -1 "${REF}" -- "${SHIPPED[@]}")"
+  # Loudly, on purpose. A silent fallback here is the landmine this whole
+  # script exists to avoid: a plausible-looking version that is quietly wrong,
+  # on a green run. Realistically this means a shallow clone (no commit in
+  # range touches the shipped set) rather than a repo of pure CI config.
+  if [ -z "${commit_epoch}" ]; then
+    echo "version.sh: no commit under '${REF}' touches the shipped file set — shallow clone? (needs fetch-depth: 0)" >&2
+    exit 1
+  fi
 fi
 now_epoch="${MINSTREL_NOW_EPOCH:-$(date -u +%s)}"
 
diff --git a/internal/server/release_version_test.go b/internal/server/release_version_test.go
index e27aafa0..1846adca 100644
--- a/internal/server/release_version_test.go
+++ b/internal/server/release_version_test.go
@@ -468,3 +468,134 @@ func TestImageBuild_StampsADerivedVersionAndAChannel(t *testing.T) {
 		t.Error("the image job no longer derives its version from ci/version.sh — the version and the APK's version can now drift apart")
 	}
 }
+
+// gitRepo builds a throwaway repo and returns its path. Commit timestamps are
+// pinned so the derivation is deterministic.
+func gitRepo(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	run := func(args ...string) {
+		t.Helper()
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(), "GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null")
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %v\n%s", args, err, out)
+		}
+	}
+	run("-c", "init.defaultBranch=main", "init", "-q")
+	run("config", "user.email", "t@example.invalid")
+	run("config", "user.name", "t")
+	return dir
+}
+
+// commitFile writes path and commits it with a pinned committer timestamp.
+func commitFile(t *testing.T, dir, path, epoch string) {
+	t.Helper()
+	full := filepath.Join(dir, path)
+	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(full, []byte("x\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	for _, args := range [][]string{{"add", "-A"}, {"commit", "-q", "-m", path}} {
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(),
+			"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+			"GIT_AUTHOR_DATE=@"+epoch+" +0000",
+			"GIT_COMMITTER_DATE=@"+epoch+" +0000",
+		)
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %v\n%s", args, err, out)
+		}
+	}
+}
+
+// versionIn runs ci/version.sh inside dir, reading real git rather than the
+// pinned-clock override, so the PATHSPEC is what is under test.
+func versionIn(t *testing.T, dir string) (string, error) {
+	t.Helper()
+	cmd := exec.Command(filepath.Join(repoRoot(t), "ci", "version.sh"), "HEAD")
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(),
+		"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+		"MINSTREL_NOW_EPOCH=1789000920",
+	)
+	out, err := cmd.CombinedOutput()
+	return string(out), err
+}
+
+// The version names what SHIPPED, so a commit that changes nothing shippable
+// must not move it.
+//
+// The failure this prevents is not the cosmetic one. The derivation is a
+// denylist precisely so that new content counts by default: the direction that
+// matters is a changed artifact keeping its OLD version, silently, on a green
+// run. This test pins the cheap half of that (CI-only commits are inert) and,
+// in the same breath, that a source commit still moves it — because a pathspec
+// typo that excluded everything would satisfy the first assertion alone.
+func TestVersionName_IgnoresCommitsThatShipNothing(t *testing.T) {
+	const (
+		shipped = "1757443736" // 2025-09-09T18:48:56Z
+		ciOnly  = "1789000920" // 2026-09-10T00:42:00Z, later
+	)
+	dir := gitRepo(t)
+	commitFile(t, dir, "internal/server/thing.go", shipped)
+	commitFile(t, dir, ".gitea/workflows/release.yml", ciOnly)
+
+	out, err := versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2025.09.09.1848") {
+		t.Errorf("a CI-only commit moved the version — the pathspec is not excluding it\n%s", out)
+	}
+
+	// ...and the pathspec must not be so broad it excludes everything.
+	commitFile(t, dir, "internal/server/other.go", ciOnly)
+	out, err = versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2026.09.10.0042") {
+		t.Errorf("a source commit did NOT move the version — the pathspec excludes too much, which is the silent-lie direction\n%s", out)
+	}
+}
+
+// android/ is deliberately NOT excluded, and that is the subtle half of the
+// list. It ships in no server image — but it is the APK's entire source, and
+// ONE script derives the version for both artifacts. Excluding it would stop
+// an Android-only commit from moving the APK's own version, which is exactly
+// the silent downgrade the versioning rework exists to prevent.
+func TestVersionName_AndroidSourcesCount(t *testing.T) {
+	dir := gitRepo(t)
+	commitFile(t, dir, "internal/server/thing.go", "1757443736")
+	commitFile(t, dir, "android/app/src/main/Thing.kt", "1789000920")
+
+	out, err := versionIn(t, dir)
+	if err != nil {
+		t.Fatalf("version.sh failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(out, "name=2026.09.10.0042") {
+		t.Errorf("an Android commit did not move the version; the APK would ship new code under its old version name\n%s", out)
+	}
+}
+
+// No shipped commit in range means a shallow clone, and the script must refuse
+// rather than emit something plausible. A wrong version builds, signs and
+// publishes perfectly happily; it surfaces later as an update channel that has
+// quietly stopped offering anything.
+func TestVersionScript_RefusesWhenNothingShippedIsInRange(t *testing.T) {
+	dir := gitRepo(t)
+	commitFile(t, dir, "ci/version.sh", "1789000920")
+
+	out, err := versionIn(t, dir)
+	if err == nil {
+		t.Fatalf("script succeeded with no shipped commit in range; it should refuse\n%s", out)
+	}
+	if strings.Contains(out, "name=") {
+		t.Errorf("script emitted a version name while refusing — that value could still be consumed\n%s", out)
+	}
+}