DEMO-04: Ship a complete developer image with compiler, SDK, and 8.3-safe assets

[rwrife]

Outcome

A clean normal developer-image build contains everything needed to compile the demo applications without host file injection or optional preexisting artifacts.

Evidence and scope

Assessment baseline: e026af0. Normal app enumeration omits cc. Developer staging lacks required public API/runtime assets and conditionally stages selected archives. The kernel and image writer both enforce 8.3 filenames, making names such as secureos_api.h, libsofpack.a, and hello.bin.manifest.json invalid.

• Add the real cc build and staging to the developer image.
• Stage a complete, explicitly enumerated set of API/ABI headers, standard headers needed by supported samples, libos/startup support, clib, compiler runtime archives, and required packaging dependencies.
• Apply DEMO-03's naming contract consistently to includes, internal header dependencies, archive search, sidecars, and documentation.
• Make missing required developer assets a build failure rather than silently skipping them.
• Include small console and graphical source samples plus concise in-guest authoring/build/run instructions; samples must use only the shipped SDK.
• Bundle existing TinyCC LGPL compliance artifacts when distributing the compiler-containing image.

Acceptance criteria

• A clean build produces boot and writable disk artifacts containing every required developer asset.
• Every staged path is legal and accessible through the guest filesystem.
• Removing a required compiler/runtime artifact causes a clear build failure.
• Both samples compile using only files supplied by the image and source changes made in the guest.
• Documentation uses working command paths and the actual shell, not a nonexistent sosh REPL.

References

• build/scripts/build.sh:41-70
• build/scripts/build_disk_image.sh:123-161
• tools/populate_disk_image.py:115-146
• kernel/fs/fs_service.c:190-233
• docs/legal/lgpl-compliance.md

Dependencies

#766, #767

Replaced backlog

Supersedes or consolidates scope from #531, #613, #540, #584, #396. Old issues are being closed as superseded, not as completed.