fix(docker): restore make docker-build by adding build directives and fixing Go version (#2700)

* fix(docker): restore `make docker-build` by adding build directives and fixing Go version

docker-compose.yml only had `image:` references with no `build:` sections,
so `docker compose build` had nothing to build. Also fixed golang:1.26.0-alpine
(nonexistent) to golang:1.25-alpine in Dockerfile.full/heavy, and removed
LICENSE from .dockerignore since scripts/copydir.go needs it as a repo-root anchor
during `go generate`.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(docker): inject version metadata ldflags in Dockerfile.launcher

Mirror the ldflags from web/Makefile (Version, GitCommit, BuildTime,
GoVersion) into the picoclaw-launcher go build command so Docker-built
launcher images include proper version/build metadata.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

docker/docker-compose.yml

@@ -4,6 +4,9 @@ services:
   #   docker compose -f docker/docker-compose.yml run --rm picoclaw-agent -m "Hello"
   # ─────────────────────────────────────────────
   picoclaw-agent:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
     image: docker.io/sipeed/picoclaw:latest
     container_name: picoclaw-agent
     profiles:
@@ -22,6 +25,9 @@ services:
   #   docker compose -f docker/docker-compose.yml --profile gateway up
   # ─────────────────────────────────────────────
   picoclaw-gateway:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
     image: docker.io/sipeed/picoclaw:latest
     container_name: picoclaw-gateway
     restart: unless-stopped
@@ -38,6 +44,9 @@ services:
   #   docker compose -f docker/docker-compose.yml --profile launcher up
   # ─────────────────────────────────────────────
   picoclaw-launcher:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile.launcher
     image: docker.io/sipeed/picoclaw:launcher
     container_name: picoclaw-launcher
     restart: unless-stopped