fix(cog-person-count): emit real signed manifest from CLI (ADR-159 A4)

cmd_manifest emitted a null skeleton (binary_sha256: null) while the
real signed manifest existed on disk at
cog/artifacts/manifests/<arch>/manifest.json.

- New manifest module include_str!-embeds the real signed manifests
  (x86_64 + arm), selected by build target arch.
- cmd_manifest parses-then-emits the embedded signed manifest, mirroring
  cog-pose-estimation manifest_roundtrips. CLI now reports the real
  binary_sha256, weights_sha256, Ed25519 signature, and honest
  build_metadata (training_class1_accuracy = 0.343).

Failing-on-old test:
manifest::tests::embedded_manifest_has_non_null_binary_sha256 (+
embedded_manifest_is_signed, embedded_manifest_id_matches_cog).
Verified end-to-end: cog-person-count manifest -> non-null sha256.

Co-Authored-By: claude-flow <ruv@ruv.net>

v2/crates/cog-person-count/src/lib.rs

@@ -9,6 +9,7 @@
 
 pub mod fusion;
 pub mod inference;
+pub mod manifest;
 pub mod publisher;
 pub mod runtime;
 

v2/crates/cog-person-count/src/main.rs

@@ -12,7 +12,6 @@ use cog_person_count::{
     publisher, COG_ID, COG_VERSION,
 };
 use serde::{Deserialize, Serialize};
-use serde_json::{json, Value};
 use std::path::PathBuf;
 
 #[derive(Parser)]
@@ -83,19 +82,11 @@ fn cmd_version() -> Result<(), Box<dyn std::error::Error>> {
 }
 
 fn cmd_manifest() -> Result<(), Box<dyn std::error::Error>> {
-    println!(
-        "{}",
-        serde_json::to_string_pretty(&json!({
-            "id": COG_ID,
-            "version": COG_VERSION,
-            "binary_url": Value::Null,
-            "binary_bytes": Value::Null,
-            "binary_sha256": Value::Null,
-            "binary_signature": Value::Null,
-            "installed_at": Value::Null,
-            "status": Value::Null,
-        }))?
-    );
+    // Emit the real, signed manifest embedded at compile time (ADR-159 §A4) —
+    // not the old hollow null skeleton. Parse-then-emit so a malformed embedded
+    // artifact fails loudly and the output is canonical JSON.
+    let spec = cog_person_count::manifest::embedded_manifest_value()?;
+    println!("{}", serde_json::to_string_pretty(&spec)?);
     Ok(())
 }
 

v2/crates/cog-person-count/src/manifest.rs

@@ -0,0 +1,77 @@
+//! Embedded signed cog manifest (ADR-100 §"manifest.json", ADR-159 §A4).
+//!
+//! The `cog-person-count manifest` subcommand emits the **real, signed**
+//! manifest the release pipeline produced — byte-for-byte the artifact served
+//! from GCS, with a real `binary_sha256`, `weights_sha256`, Ed25519
+//! `binary_signature`, and honest `build_metadata` (e.g. `training_class1_accuracy
+//! = 0.343`, not inflated). The previous implementation printed a hollow
+//! skeleton with `binary_sha256: null`, which made the CLI look unsigned even
+//! though the signed manifest existed on disk.
+//!
+//! The matching manifest for the build's target arch is selected via `cfg!`.
+
+/// Real signed manifest for `x86_64-unknown-linux-gnu`.
+pub const MANIFEST_X86_64: &str =
+    include_str!("../cog/artifacts/manifests/x86_64/manifest.json");
+
+/// Real signed manifest for `aarch64`/`arm` (the Seed appliance).
+pub const MANIFEST_ARM: &str = include_str!("../cog/artifacts/manifests/arm/manifest.json");
+
+/// The embedded signed manifest matching the build's target arch.
+pub fn embedded_manifest_str() -> &'static str {
+    if cfg!(any(target_arch = "aarch64", target_arch = "arm")) {
+        MANIFEST_ARM
+    } else {
+        MANIFEST_X86_64
+    }
+}
+
+/// Parse the embedded manifest into canonical JSON. Returns an error if the
+/// embedded artifact is malformed (so the CLI fails loudly rather than printing
+/// garbage).
+pub fn embedded_manifest_value() -> Result<serde_json::Value, serde_json::Error> {
+    serde_json::from_str(embedded_manifest_str())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// ADR-159 §A4 — the embedded manifest the CLI emits must carry a real
+    /// `binary_sha256` (the field the old hollow `cmd_manifest` left null).
+    #[test]
+    fn embedded_manifest_has_non_null_binary_sha256() {
+        let v = embedded_manifest_value().expect("embedded manifest parses");
+        let sha = v.get("binary_sha256").and_then(|s| s.as_str());
+        assert!(
+            sha.is_some(),
+            "embedded manifest must have a non-null binary_sha256 (got {:?})",
+            v.get("binary_sha256")
+        );
+        let sha = sha.unwrap();
+        assert_eq!(sha.len(), 64, "binary_sha256 must be a 32-byte hex digest");
+        assert!(
+            sha.chars().all(|c| c.is_ascii_hexdigit()),
+            "binary_sha256 must be hex"
+        );
+    }
+
+    #[test]
+    fn embedded_manifest_is_signed() {
+        let v = embedded_manifest_value().expect("parse");
+        assert!(
+            v.get("binary_signature").and_then(|s| s.as_str()).is_some(),
+            "embedded manifest must carry an Ed25519 binary_signature"
+        );
+        assert_eq!(
+            v.get("sig_algo").and_then(|s| s.as_str()),
+            Some("Ed25519")
+        );
+    }
+
+    #[test]
+    fn embedded_manifest_id_matches_cog() {
+        let v = embedded_manifest_value().expect("parse");
+        assert_eq!(v.get("id").and_then(|s| s.as_str()), Some(crate::COG_ID));
+    }
+}