## What changed
- Consolidate v2 rollout summaries into `memory_summary.md` without generating `raw_memories.md` or requiring `MEMORY.md`. Validate the summary's required sections and size below 10,000 UTF-8 bytes.
- Add v2 read instructions for selective history retrieval, evidence-grounded preferences, citations, and explicit memory edits. Split injected instructions into fragments to preserve the complete summary within fragment byte limits.
- Record memory citation usage in the store selected by `memories.version`.
## Testing
Add coverage for v2 consolidation without a handbook, summary validation, version-isolated memory reads, and resetting both memory versions while preserving threads.
GitOrigin-RevId: 1d895fb4a23a973f1a45ba03be07a1f480c10227
## Why
The memories extension now owns the read-path developer instructions it
injects at thread start. Keeping that prompt builder and template in
`codex-memories-read` left the extension depending on a helper crate for
extension-specific prompt assembly, and kept async template/truncation
dependencies in the read crate after the remaining read surface no
longer needed them.
## What changed
- Moved `prompts.rs`, its tests, and `templates/memories/read_path.md`
from `memories/read` into `ext/memories`.
- Wired `MemoryExtension` to call the local prompt builder and added the
moved templates to `ext/memories/BUILD.bazel` compile data.
- Removed the now-unused prompt export and prompt-related dependencies
from `codex-memories-read`.
## Testing
- Not run locally.
jif