fix(ci): install libprotobuf-dev in the Debian 12 release containers

[jja725]

Fixes the two failing debian12 rows in the v0.1.5 release run. Regression from #53, which was mine.

What broke

Both debian12 rows died at Configure + build about 14 minutes in, while the ubuntu-24.04 rows succeeded:

error: failed to run custom build command for `lance-encoding v7.0.0-beta.7`
Caused by:
  Error: Custom { kind: Other, error: "protoc failed: google/protobuf/empty.proto: File not found.
  encodings_v2_0.proto:8:1: Import \"google/protobuf/empty.proto\" was not found or had errors.
  encodings_v2_0.proto:343:5: \"google.protobuf.Empty\" is not defined." }

protoc installed fine. What was missing were the well-known type definitions under /usr/include/google/protobuf/, which lance-encoding's build script imports.

Root cause

On Debian and Ubuntu those .proto files ship in libprotobuf-dev, and protobuf-compiler only Recommends it rather than depending on it. The ubuntu-24.04 rows run a plain apt-get install -y protobuf-compiler, which honors Recommends and picks it up implicitly. The container step I added in #53 uses --no-install-recommends, which silently dropped it.

Isolated by comparing all four combinations in real containers:

environment	empty.proto	import compiles
debian:12, protobuf-compiler --no-install-recommends	missing	FAILS
debian:12, protobuf-compiler (recommends on)	present	OK
debian:12, protobuf-compiler libprotobuf-dev	present	OK
ubuntu:24.04, protobuf-compiler	present	OK

Row 1 reproduces the CI failure with the same two error strings. Rows 2 and 3 both resolve it.

Why this fix

Adding libprotobuf-dev explicitly rather than dropping --no-install-recommends. It names the actual dependency, and it keeps the other eleven packages from pulling in their own recommends.

Test plan

The controlled comparison above was run in real debian:12 and ubuntu:24.04 containers. actionlint reports no new findings (the two SC2035/SC2129 hits in the publish job predate #53).

Full end-to-end proof is the release workflow itself. Worth re-dispatching Release at v0.1.5 once this lands, before cutting anything new.

Note for #50

If #50 lands, this becomes moot for the same reason: its protoc install extracts include/* from the upstream release zip, which is exactly the well-known types. That approach sidesteps the Recommends trap entirely and is arguably the more robust one.

🤖 Generated with Claude Code