fix: identity binding + JSON endpoint + Phase 5 test script

- identity_binding.rs: fix i32->i64 type mismatch, COALESCE name column
- identity_api.rs: get_identity_json fallback to DB if file missing
- test_m5api_phase5.sh: fixed variable expansion, updated request bodies
- Phase 5: 21/23 passed (2 known: multipart + proxy 404)

src/api/identity_api.rs

@@ -792,6 +792,7 @@ async fn get_profile_image(
 }
 
 async fn get_identity_json(
+    State(state): State<crate::api::server::AppState>,
     Path(identity_uuid): Path<String>,
 ) -> Result<(StatusCode, [(String, String); 1], Vec<u8>), StatusCode> {
     let clean = identity_uuid.replace('-', "");
@@ -800,6 +801,8 @@ async fn get_identity_json(
     } else {
         identity_uuid.clone()
     };
+
+    // 1. Try file system first
     for u in [&clean, &identity_uuid, &with_hyphens] {
         let p = crate::core::identity::storage::identity_file_path(u);
         if p.exists() {
@@ -811,7 +814,46 @@ async fn get_identity_json(
             ));
         }
     }
-    Err(StatusCode::NOT_FOUND)
+
+    // 2. Fallback: Generate JSON from DB
+    use crate::core::identity::storage::{IdentityFile, FileBinding};
+    let record = state.db.get_identity_by_uuid(&clean).await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
+        .ok_or(StatusCode::NOT_FOUND)?;
+
+    let id = record.id as i64;
+    let bindings: Vec<FileBinding> = {
+        let fd_table = crate::core::db::schema::table_name("face_detections");
+        let rows = sqlx::query_as::<_, (String, Vec<i32>, i64)>(
+            &format!("SELECT fd.file_uuid, COALESCE(array_agg(DISTINCT fd.trace_id) FILTER (WHERE fd.trace_id IS NOT NULL), '{{}}'::int[]), COUNT(*)::bigint                       FROM {} fd WHERE fd.identity_id = $1 GROUP BY fd.file_uuid ORDER BY fd.file_uuid", fd_table)
+        ).bind(id).fetch_all(state.db.pool()).await.unwrap_or_default();
+        rows.into_iter().map(|(fu, tids, cnt)| FileBinding {
+            file_uuid: fu, trace_ids: tids, face_count: cnt,
+        }).collect()
+    };
+
+    let fmt_time = |dt: Option<chrono::DateTime<chrono::Utc>>| -> String {
+        dt.map(|d| d.to_rfc3339()).unwrap_or_else(|| chrono::Utc::now().to_rfc3339())
+    };
+
+    let file = IdentityFile {
+        version: 1,
+        identity_uuid: record.uuid.clone(),
+        name: record.name.clone(),
+        identity_type: record.identity_type.clone(),
+        source: record.source.clone(),
+        status: record.status.clone(),
+        tmdb_id: record.tmdb_id,
+        tmdb_profile: record.tmdb_profile.clone(),
+        metadata: record.metadata.clone(),
+        file_bindings: bindings,
+        created_at: fmt_time(record.created_at),
+        updated_at: fmt_time(record.updated_at),
+    };
+
+    let json = serde_json::to_string_pretty(&file).unwrap_or_default();
+    let bytes = json.into_bytes();
+    Ok((StatusCode::OK, [("content-type".to_string(), "application/json".to_string())], bytes))
 }
 
 // ── Experiment: Identity Text Search ──────────────────────────