docs: Add composefs-rs crates to internals rustdoc

These external git dependencies don't have docs on docs.rs, so include
them in the internal documentation alongside our workspace crates.

Assisted-by: OpenCode (Opus 4.5)
Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

docs/Dockerfile.mdbook

@@ -17,6 +17,8 @@ RUN --mount=type=cache,target=/src/target <<EORUN
 set -xeuo pipefail
 # Build rustdoc for internal crates
 cargo doc --workspace --no-deps --document-private-items
+# Also build docs for key external git dependencies (not on docs.rs)
+cargo doc --no-deps --document-private-items -p composefs -p composefs-boot -p composefs-oci
 # Build mdbook
 cd docs
 mdbook-mermaid install .

docs/src/internals.md

@@ -22,3 +22,11 @@ These are intended for developers working on bootc itself, not for external cons
 - [bootc-internal-blockdev](internals/bootc_internal_blockdev/index.html) - Block device handling
 - [bootc-sysusers](internals/bootc_sysusers/index.html) - systemd-sysusers implementation
 - [bootc-tmpfiles](internals/bootc_tmpfiles/index.html) - systemd-tmpfiles implementation
+
+## External git crates
+
+These crates are pulled from git and are not published to crates.io (so not on docs.rs).
+
+- [composefs](internals/composefs/index.html) - Core composefs library
+- [composefs-boot](internals/composefs_boot/index.html) - Boot support for composefs
+- [composefs-oci](internals/composefs_oci/index.html) - OCI integration for composefs