Migrate from Debian Bullseye to Bookworm

Debian Bullseye has reached EOL and bullseye-backports repository
is no longer available, causing build failures. This updates all
Dockerfiles to use Debian Bookworm (current stable release).

Changes:
- Update all base images from bullseye to bookworm
- Update backports repository configuration
- Verified build successfully completes on both amd64 and arm64

Author: lambdalisue

dockerfiles/neovim

@@ -1,6 +1,6 @@
 # syntax=docker.io/docker/dockerfile:1.4
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as neovim
+FROM debian:bookworm-backports as neovim
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -32,7 +32,7 @@ RUN git clone https://github.com/neovim/neovim \
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as deno
+FROM debian:bookworm-backports as deno
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -50,7 +50,7 @@ RUN curl -fsSL https://deno.land/install.sh | DENO_INSTALL=/opt/deno sh -s ${DEN
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as denops
+FROM debian:bookworm-backports as denops
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -72,15 +72,15 @@ RUN mkdir -p denops.vim \
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-slim as runtime
+FROM debian:bookworm-slim as runtime
 ENV DEBIAN_FRONTEND=noninteractive
 
 LABEL org.opencontainers.image.url https://github.com/orgs/vim-denops/packages/container/package/neovim
 LABEL org.opencontainers.image.source https://github.com/vim-denops/denops-dockerfile
 
 # Prefer to use Debian Backports
 # https://backports.debian.org/
-RUN echo 'deb http://deb.debian.org/debian bullseye-backports main' > /etc/apt/sources.list.d/backports.list
+RUN echo 'deb http://deb.debian.org/debian bookworm-backports main' > /etc/apt/sources.list.d/backports.list
 
 # Runtime environment
 ENV LC_ALL=C.UTF-8 \

dockerfiles/vim

@@ -1,6 +1,6 @@
 # syntax=docker.io/docker/dockerfile:1.4
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as vim
+FROM debian:bookworm-backports as vim
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -26,7 +26,7 @@ RUN make install
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as deno
+FROM debian:bookworm-backports as deno
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -44,7 +44,7 @@ RUN curl -fsSL https://deno.land/install.sh | DENO_INSTALL=/opt/deno sh -s ${DEN
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-backports as denops
+FROM debian:bookworm-backports as denops
 ENV DEBIAN_FRONTEND=noninteractive
 
 # Install requirements
@@ -66,15 +66,15 @@ RUN mkdir -p denops.vim \
 
 
 #------------------------------------------------------------------------------------------------------------
-FROM debian:bullseye-slim as runtime
+FROM debian:bookworm-slim as runtime
 ENV DEBIAN_FRONTEND=noninteractive
 
 LABEL org.opencontainers.image.url https://github.com/orgs/vim-denops/packages/container/package/vim
 LABEL org.opencontainers.image.source https://github.com/vim-denops/denops-dockerfile
 
 # Prefer to use Debian Backports
 # https://backports.debian.org/
-RUN echo 'deb http://deb.debian.org/debian bullseye-backports main' > /etc/apt/sources.list.d/backports.list
+RUN echo 'deb http://deb.debian.org/debian bookworm-backports main' > /etc/apt/sources.list.d/backports.list
 
 # Runtime environment
 ENV LC_ALL=C.UTF-8 \