Closes the gaps between "scaffolded" and "safe to depend on by a real consumer app" — specifically the open questions and untested patterns called out in the problem statement.

Codegen parser decision

Resolved open-questions.md item 5: keep the tokenizer. It already satisfies "fail loudly, never silently" — throws CodegenException on any unrecognised construct. libclang would add ~50 MB of native binaries per platform to the dotnet tool NuGet with no correctness gain within the blittable-only constraint.

DSP fixture (native/dsp_fixture/)

Adds the two real-consumer parameter patterns ferrum_add(int,int) never exercised:

// float* buffer + int32_t length
void ferrum_dsp_scale(float* buf, int32_t len, float factor);

// blittable struct out-parameter
void ferrum_dsp_stats(const float* buf, int32_t len, FerrumDspStats* result);

• FerrumDspStats — [StructLayout(Sequential)] with float min_val/max_val/mean + int32_t count
• FerrumDspBindings.cs pre-generated and committed; compiles in the test project via [LibraryImport]
• 15 new xUnit tests (48 total) covering struct fields, pointer params, const stripping, void returns, emitter round-trip, and a regression guard that fails if the committed bindings file drifts from tool output
• Fixed a block-comment bug in the header where float*/int-length text prematurely closed a /** */ comment, causing a parse error

Build pipeline

• native/CMakeLists.txt — added FERRUM_BUILD_DSP_FIXTURE option + add_subdirectory(dsp_fixture)
• native-build.yml — matrix now builds both fixtures across all iOS slices and Android ABIs
• codegen-tests.yml — smoke test runs codegen against both headers; verifies [LibraryImport], struct, and function names in output

Distribution model

Resolved open-questions.md item 1: NuGet + source template. NuGet metadata already existed in both .csproj files. Added templates/Ferrum.Templates.csproj to package maui-ferrum as a dotnet new install Ferrum.Templates package; wired into Ferrum.sln.

NativeAOT real-device verification

Cannot be automated in CI (requires provisioned hardware + Apple Developer credentials). Added explicit manual steps to getting-started.md with a TODO marker — covers both fixtures, expected console checks, and what to record in the PR.