refactor: derive git info inside Docker instead of --build-arg

- Remove .git from .dockerignore so it's available in Docker build context
- Install git in Docker image (apt-get)
- Remove ARG/ENV GIT_COMMIT_SHORT/FULL from Dockerfile
- Remove --build-arg from Makefile docker target
- Simplify build.js to use git CLI directly (no env var indirection)

build.js already had fallback logic to shell out to git; now that .git
is present in the build context, it works directly without needing
values passed in from outside Docker.

.dockerignore

@@ -1,4 +1,3 @@
-.git
 node_modules
 .DS_Store
 dist

Dockerfile

@@ -1,7 +1,7 @@
 # node:22-slim (22.x LTS), 2026-02-24
 FROM node@sha256:5373f1906319b3a1f291da5d102f4ce5c77ccbe29eb637f072b6c7b70443fc36
 
-RUN apt-get update && apt-get install -y --no-install-recommends make && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y --no-install-recommends make git && rm -rf /var/lib/apt/lists/*
 RUN corepack enable && corepack prepare yarn@1.22.22 --activate
 
 WORKDIR /app
@@ -11,10 +11,5 @@ RUN yarn install --frozen-lockfile
 
 COPY . .
 
-ARG GIT_COMMIT_SHORT=unknown
-ARG GIT_COMMIT_FULL=unknown
-ENV GIT_COMMIT_SHORT=${GIT_COMMIT_SHORT}
-ENV GIT_COMMIT_FULL=${GIT_COMMIT_FULL}
-
 RUN make check
 RUN make build

Makefile

@@ -33,10 +33,7 @@ dev:
 	@yarn run build --watch 2>&1
 
 docker:
-	@docker build \
+	@docker build -t autistmask .
-		--build-arg GIT_COMMIT_SHORT=$$(git rev-parse --short HEAD 2>/dev/null || echo unknown) \
-		--build-arg GIT_COMMIT_FULL=$$(git rev-parse HEAD 2>/dev/null || echo unknown) \
-		-t autistmask .
 
 hooks:
 	@echo "Installing pre-commit hook..."

build.js

@@ -15,8 +15,7 @@ function getBuildInfo() {
     const pkg = JSON.parse(
         fs.readFileSync(path.join(__dirname, "package.json"), "utf8"),
     );
-    let commitHash = process.env.GIT_COMMIT_SHORT || "unknown";
+    let commitHash = "unknown";
-    if (commitHash === "unknown") {
     try {
         commitHash = execSync("git rev-parse --short HEAD", {
             encoding: "utf8",
@@ -24,9 +23,7 @@ function getBuildInfo() {
     } catch (_) {
         // not a git repo or git not available
     }
-    }
+    let commitHashFull = "unknown";
-    let commitHashFull = process.env.GIT_COMMIT_FULL || "unknown";
-    if (commitHashFull === "unknown") {
     try {
         commitHashFull = execSync("git rev-parse HEAD", {
             encoding: "utf8",
@@ -34,7 +31,6 @@ function getBuildInfo() {
     } catch (_) {
         // not a git repo or git not available
     }
-    }
     return {
         version: pkg.version,
         license: pkg.license,