feat: implement audit logs system, request extractor, admin log panel, and dedicated documentation

- Added an enterprise-grade, request-scoped AuditLogger extractor in Axum.
- Configured MongoDB persistence for structured, replayable audit logs (capturing timestamp, user, action, type, payload snapshot, client IP with proxy header support, and User-Agent).
- Created a live Administrator console at /auth/audit to filter and inspect log events.
- Re-architected documentation by moving Design Wiki pages out of /components into a dedicated /docs route.
- Published logging architecture documentation at /docs/logging.

src/developers/handlers.rs

@@ -4,6 +4,7 @@ use axum::{
     http::StatusCode,
     response::{Html, IntoResponse, Redirect, Response},
 };
+use crate::audit::AuditLogger;
 use mongodb::bson::oid::ObjectId;
 use serde::Deserialize;
 use crate::common::errors::AppError;
@@ -56,6 +57,7 @@ struct DeveloperSearchResultsTemplate {
 
 pub async fn get_list(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
 ) -> Result<Response, AppError> {
     let Some(user) = user_opt else {
@@ -65,6 +67,14 @@ pub async fn get_list(
     let _ = dev_repo.ensure_seeded(&user.user_id).await;
     let developers = dev_repo.find_all_by_user(&user.user_id).await?;
 
+    audit.log(
+        "View",
+        "Developer",
+        None,
+        Some("Viewed list of all developers".to_string()),
+        None
+    ).await;
+
     Ok(HtmlTemplate(DeveloperListTemplate {
         username: user.username,
         authenticated: true,
@@ -82,6 +92,7 @@ pub struct CreateDevForm {
 
 pub async fn post_create(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
     Form(payload): Form<CreateDevForm>,
 ) -> Result<Response, AppError> {
@@ -101,13 +112,28 @@ pub async fn post_create(
         .filter(|s| !s.is_empty())
         .collect();
 
-    dev_repo.create(&user.user_id, name, email, skills).await?;
+    let new_dev = dev_repo.create(&user.user_id, name, email, skills).await?;
+
+    let payload_val = serde_json::json!({
+        "name": new_dev.name,
+        "email": new_dev.email,
+        "skills": new_dev.skills,
+    });
+
+    audit.log(
+        "Create",
+        "Developer",
+        new_dev.id,
+        Some(format!("Created developer: {}", name)),
+        Some(payload_val)
+    ).await;
 
     Ok(Redirect::to("/developers").into_response())
 }
 
 pub async fn get_edit(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
     Path(dev_id_str): Path<String>,
 ) -> Result<Response, AppError> {
@@ -123,6 +149,14 @@ pub async fn get_edit(
         return Err(AppError::Unauthorized("Developer not found".to_string()));
     };
 
+    audit.log(
+        "View",
+        "Developer",
+        Some(dev_id),
+        Some(format!("Viewed edit page for developer: {}", developer.name)),
+        None
+    ).await;
+
     Ok(HtmlTemplate(DeveloperEditTemplate {
         username: user.username,
         authenticated: true,
@@ -133,6 +167,7 @@ pub async fn get_edit(
 
 pub async fn post_update(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
     Path(dev_id_str): Path<String>,
     Form(payload): Form<CreateDevForm>,
@@ -156,13 +191,41 @@ pub async fn post_update(
         .filter(|s| !s.is_empty())
         .collect();
 
+    let dev_before = dev_repo.find_by_id(&dev_id, &user.user_id).await?;
+
     dev_repo.update(&dev_id, &user.user_id, name, email, skills).await?;
 
+    let dev_after = dev_repo.find_by_id(&dev_id, &user.user_id).await?;
+
+    if let (Some(dbef), Some(daft)) = (dev_before, dev_after) {
+        let payload_val = serde_json::json!({
+            "before": {
+                "name": dbef.name,
+                "email": dbef.email,
+                "skills": dbef.skills,
+            },
+            "after": {
+                "name": daft.name,
+                "email": daft.email,
+                "skills": daft.skills,
+            }
+        });
+
+        audit.log(
+            "Update",
+            "Developer",
+            Some(dev_id),
+            Some(format!("Updated developer details for: {}", name)),
+            Some(payload_val)
+        ).await;
+    }
+
     Ok(Redirect::to("/developers").into_response())
 }
 
 pub async fn post_delete(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
     Path(dev_id_str): Path<String>,
 ) -> Result<Response, AppError> {
@@ -173,8 +236,26 @@ pub async fn post_delete(
     let dev_id = ObjectId::parse_str(&dev_id_str)
         .map_err(|_| AppError::BadRequest("Invalid developer identifier".to_string()))?;
 
+    let dev_to_delete = dev_repo.find_by_id(&dev_id, &user.user_id).await?;
+
     dev_repo.delete(&dev_id, &user.user_id).await?;
 
+    if let Some(dd) = dev_to_delete {
+        let payload_val = serde_json::json!({
+            "name": dd.name,
+            "email": dd.email,
+            "skills": dd.skills,
+        });
+
+        audit.log(
+            "Delete",
+            "Developer",
+            Some(dev_id),
+            Some(format!("Deleted developer: {}", dd.name)),
+            Some(payload_val)
+        ).await;
+    }
+
     Ok(Redirect::to("/developers").into_response())
 }
 
@@ -185,6 +266,7 @@ pub struct SearchQuery {
 
 pub async fn get_search(
     State(dev_repo): State<MongoDeveloperRepository>,
+    audit: AuditLogger,
     user_opt: Option<AuthenticatedUser>,
     Query(params): Query<SearchQuery>,
 ) -> Result<Response, AppError> {
@@ -200,6 +282,19 @@ pub async fn get_search(
 
     let matched_devs = dev_repo.search_by_name(&user.user_id, query_str).await?;
 
+    let payload_val = serde_json::json!({
+        "query": query_str,
+        "results_count": matched_devs.len(),
+    });
+
+    audit.log(
+        "Search",
+        "Developer",
+        None,
+        Some(format!("Searched developers with query: '{}'", query_str)),
+        Some(payload_val)
+    ).await;
+
     Ok(HtmlTemplate(DeveloperSearchResultsTemplate {
         developers: matched_devs,
     })

src/developers/mod.rs

@@ -13,6 +13,7 @@ pub fn router<S>() -> Router<S>
 where
     Config: axum::extract::FromRef<S>,
     MongoDeveloperRepository: axum::extract::FromRef<S>,
+    mongodb::Database: axum::extract::FromRef<S>,
     S: Clone + Send + Sync + 'static,
 {
     Router::new()