Add append-only package writer with atomic validated publication

README.md

@@ -1,6 +1,6 @@
 # VianoBugAnalysis
 
-Project-independent foundations for reading and validating long-lived ZIP case
+Project-independent foundations for reading, validating and extending ZIP case
 packages. The authoritative design is [docs/architecture.md](docs/architecture.md).
 The implemented v1 contract is documented in
 [docs/package-format-v1.md](docs/package-format-v1.md).
@@ -13,5 +13,5 @@ python -m venv .venv
 .\.venv\Scripts\python.exe -m pytest
 ```
 
-This milestone includes no package writer, lifecycle worker, CaseBuilder, LLM,
+This milestone includes no lifecycle worker, CaseBuilder, LLM,
 case interpretation, hypothesis generation or investigation tools.