Replace docker compose with persistent per-project lifecycle

Move from docker compose run to a Python-managed container lifecycle.
Each project now gets a dedicated container that is started on demand
and stopped when opencode exits, instead of being recreated each time.

Use a shared home directory across projects so configurations presist.

The container are not destroyed, so tools and caches can be installed
specifically for a project by opencode itself once and reused, while
still avoiding long-running containers.

Dockerfile

@@ -10,9 +10,11 @@ RUN pacman -Syu --noconfirm \
         ca-certificates \
         bash \
         less \
-        ripgrep && \
+        ripgrep \
+        sudo && \
     groupadd -g ${GID} ${USERNAME} && \
     useradd -m -u ${UID} -g ${GID} -s /bin/bash ${USERNAME} && \
+    echo "${USERNAME} ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers && \
     pacman -Scc --noconfirm
 
 WORKDIR /tmp
@@ -20,12 +22,8 @@ USER ${USERNAME}
 
 RUN git clone https://aur.archlinux.org/opencode-bin.git && \
     cd opencode-bin && \
-    makepkg --noconfirm
+    makepkg --syncdeps --noconfirm --install && \
+    sudo rm -rf /tmp/opencode-bin && \
+    sudo pacman -Scc --noconfirm
 
-USER root
-RUN pacman -U --noconfirm /tmp/opencode-bin/*.pkg.tar.zst && \
-    rm -rf /tmp/opencode-bin && \
-    pacman -Scc --noconfirm
-
-USER ${USERNAME}
 WORKDIR /home/${USERNAME}