feat(build): add system CA root mode (#2324)

* feat(build): add system CA root mode

Allow distro builds to use native trust stores for supervisor upstream TLS while keeping bundled Mozilla roots as the default. Avoid bundled root crates in system-ca-roots builds by using native-root TLS features and z3 0.20.

Signed-off-by: Adam Miller <admiller@redhat.com>

* fix(build): keep CA root feature in telemetry-off verification

The telemetry-off task uses --no-default-features which now disables
bundled-ca-roots in addition to telemetry, triggering the compile_error
guard. Re-enable bundled-ca-roots explicitly so the task verifies only
telemetry compilation.

Signed-off-by: Scott Burdine <sburdine@nvidia.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* fix(sdk): disable oauth2 default features to prevent webpki-roots leak

The bare `oauth2 = "5"` dependency re-enabled default features
(rustls-tls → reqwest/rustls-tls → webpki-roots), defeating the
system-ca-roots feature gate. Mirror the CLI fix: disable defaults
and enable only the `reqwest` feature.

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* refactor(build): simplify CA root selection to single feature toggle

Replace mutually exclusive bundled-ca-roots / system-ca-roots features
with a single bundled-ca-roots toggle. Disabling it implies system roots
via rustls-native-certs, which is now a regular (non-optional) dependency.
This fixes cargo --all-features and simplifies the distro build interface
from --no-default-features --features system-ca-roots to just
--no-default-features.

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* feat(build): add system-ca-roots convenience alias and fix verify task

Add a system-ca-roots feature alias on openshell-sandbox that includes
all other defaults (telemetry) except bundled-ca-roots, so distro
builds can use --no-default-features --features system-ca-roots without
manually re-adding unrelated defaults. Update the verify CI task to use
the alias and scope checks to the sandbox package. Fix task description
to use "build mode" terminology instead of implying a Cargo feature.

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* ci: fix system CA roots step name to use build mode terminology

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* refactor(sandbox): reorder features to place system-ca-roots alias near default

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

* fix(proxy): unwrap Result from build_upstream_client_config in tests

The function signature changed to return Result but the test call sites
were not updated, causing type mismatch compilation errors in CI.

Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Signed-off-by: politerealism <burdcat17@gmail.com>

---------

Signed-off-by: Adam Miller <admiller@redhat.com>
Signed-off-by: Scott Burdine <sburdine@nvidia.com>
Signed-off-by: politerealism <burdcat17@gmail.com>
Signed-off-by: Quinn Burdine <sburdine@redhat.com>
Co-authored-by: Adam Miller <admiller@redhat.com>

Author: politerealism

.github/workflows/branch-checks.yml

@@ -127,6 +127,9 @@ jobs:
       - name: Verify telemetry can be compiled out
         run: mise run rust:verify:telemetry-off
 
+      - name: Verify system CA roots build mode compiles and excludes bundled Mozilla roots
+        run: mise run rust:verify:system-ca-roots
+
       - name: sccache stats
         if: always()
         run: |