[codex] Consolidate shared prompts in codex-prompts (#25151)

## Why

`codex_core` is consistently a bottleneck for incremental builds during
iteration. The simplest fix is to make the crate smaller.

## Summary

`codex-core` owns several reusable prompt renderers and static prompt
assets, which makes the crate harder to split apart.

Rename `codex-review-prompts` to `codex-prompts` and move shared review,
goal, permissions, compaction, realtime, hierarchical AGENTS.md, and
`apply_patch` prompts into it. Move prompt-only tests and update
consumers and `CODEOWNERS`.

## Validation

- `just test -p codex-prompts -p codex-apply-patch`
- `just test -p codex-core prompt_caching`
- Bazel builds for the affected crates

codex-rs/core/src/agents_md.rs

@@ -25,15 +25,13 @@ use codex_exec_server::Environment;
 use codex_exec_server::ExecutorFileSystem;
 use codex_exec_server::LOCAL_FS;
 use codex_features::Feature;
+use codex_prompts::HIERARCHICAL_AGENTS_MESSAGE;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use dunce::canonicalize as normalize_path;
 use std::io;
 use toml::Value as TomlValue;
 use tracing::error;
 
-pub(crate) const HIERARCHICAL_AGENTS_MESSAGE: &str =
-    include_str!("../hierarchical_agents_message.md");
-
 /// Default filename scanned for AGENTS.md instructions.
 pub const DEFAULT_AGENTS_MD_FILENAME: &str = "AGENTS.md";
 /// Preferred local override for AGENTS.md instructions.