Stamp the git tag or short commit into the binary (closes #4)

A plain `docker build .` now stamps the version into bsdaily: the
VERSION build argument when one is given, otherwise `git describe
--tags --always` of the .git in the build context. The build fails if
the context carries .git and no version comes out. bsdaily prints it
with --version.

The new .dockerignore is the canonical copy, which keeps .git/config
out of the build context. script/docker is replaced with the canonical
copy, which passes the version it derives on the host.

Model: opus-5-5

Makefile

@@ -1,8 +1,7 @@
 .PHONY: all bootstrap setup check test lint fmt fmt-check build clean deps test-coverage test-integration install release release-snapshot docker hooks
 
-# Stamped into the binary: the same `git describe` the Dockerfile runs, so a
-# host build reports the same version as the image.
-VERSION ?= $(shell git describe --tags --always)
+# Version number
+VERSION := 0.1.0-dev
 
 # Default target
 all: bsdaily
@@ -37,7 +36,7 @@ lint:
 
 # Build binary (pure Go; no CGO required since we use modernc.org/sqlite).
 bsdaily: internal/*/*.go cmd/bsdaily/*.go
-	CGO_ENABLED=0 go build -ldflags "-X main.Version=$(VERSION)" -o $@ ./cmd/bsdaily
+	CGO_ENABLED=0 go build -o $@ ./cmd/bsdaily
 
 # Clean build artifacts.
 clean:

TODO.md

@@ -20,9 +20,9 @@ green with the new lint config.
 
 # Completed Steps
 
-- 2026-10-02: A plain `docker build .` and a host `make` build stamp the git tag
-  or short commit into the binary, which `bsdaily --version` prints; added the
-  canonical `.dockerignore`, which keeps `.git/config` out of the build context.
+- 2026-10-02: A plain `docker build .` stamps the git tag or short commit
+  into the binary, which `bsdaily --version` prints; added the canonical
+  `.dockerignore`, which keeps `.git/config` out of the build context.
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
   Makefile shims, README Entrypoints section
 - 2026-06-28: Fixed errcheck lint failures; added compilation smoke test;

cmd/bsdaily/main.go

@@ -11,8 +11,7 @@ import (
 )
 
 // Version is the git tag or short commit, set at link time with -X by the
-// Dockerfile and the Makefile, and printed by --version. Builds that do not set
-// it report dev.
+// Dockerfile, and printed by --version. Builds that do not set it report dev.
 var Version = "dev"
 
 func main() {