Complete native codegen milestone gate (#50)

codegen/README.md

@@ -62,6 +62,14 @@ IDs or truncated payloads without panicking. Generated tests round-trip all 483
 packet types and exercise every truncation boundary, while focused fixtures
 assert exact reference bytes and malformed-input behavior.
 
+The generated packet and block APIs also implement the golden generator's
+`PacketToOSD`, `PacketFromOSD`, `ToOSD`, and `FromOSD` behavior. This includes
+little-endian binary encoding for unsigned 32- and 64-bit values, permissive
+LLSD conversions, omission of absent map fields, one-element arrays for single
+blocks, exact replacement of variable blocks, and bounded updates of
+fixed-repeat blocks. The all-fields test round-trips every packet through both
+wire bytes and LLSD maps.
+
 Generation also compares all packet, block, field, field-type, and `PacketType`
 entries against the pinned compiled public API catalog. This rejects a template
 parser or naming change even if the emitted Rust would otherwise compile. The
@@ -131,6 +139,13 @@ Verify hashes and reject stale output without writing:
 cargo run -p libremetaverse-codegen -- check
 ```
 
+Generate into an empty temporary tree while continuing to read the pinned
+inputs from this checkout:
+
+```console
+cargo run -p libremetaverse-codegen -- generate-to /tmp/metacrate-codegen
+```
+
 Maintainers can refresh the vendored snapshots from an explicitly supplied
 checkout. The command verifies all six golden generator hashes and all input
 hashes before writing, so a different upstream revision is rejected:
@@ -145,3 +160,28 @@ manifest records by stable IDs, emits provenance-rich generated headers, and
 always terminates output with one LF. Tests generate every registered output
 twice in memory and require byte identity before comparing with the checked-in
 files.
+
+## Completion gate
+
+The complete milestone gate regenerates `source_manifest.rs`,
+`packet_catalog.rs`, `visual_catalog.rs`, `foliage_catalog.rs`,
+`skeleton_catalog.rs`, `attention_catalog.rs`, and `genepool_catalog.rs` in an
+isolated temporary directory and byte-compares them with the checked-in files.
+It also verifies the six golden generator records (`PacketSourceGenerator`,
+`VisualParamGenerator`, `SkeletonGenerator`, `AttentionsGenerator`,
+`TreesGenerator`, and `GenepoolGenerator`), all eight pinned input names and
+hashes, generated headers and licenses, complete public API ledgers/shims and
+the compile fixture, native packet LLSD implementations, and the absence of
+.NET/Roslyn dependencies or build-script invocations.
+
+Run the normal gate after generating a clean Rust release build:
+
+```console
+cargo build --workspace --release --locked
+python3 tools/check_codegen_gate.py --release-dir target/release
+cargo check --manifest-path tests/api-compile/Cargo.toml --locked
+```
+
+The release-directory option additionally scans actual artifacts for managed
+runtime names and markers. The Gitea workflow runs these commands from a clean
+checkout using only `ubuntu-latest`.