chore: apply cargo fmt + clippy cleanup across crate

Silence forward-looking dead_code on unused DAO modules, annotate
individual placeholder items, rewrite tautological assert!(true/false)
in token tests as panic! arms, and pick up fmt drift.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/database/calendar_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;
 use serde::Serialize;

src/database/daily_summary_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use chrono::NaiveDate;
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;

src/database/insights_dao.rs

@@ -31,6 +31,7 @@ pub trait InsightDao: Sync + Send {
         paths: &[String],
     ) -> Result<Option<PhotoInsight>, DbError>;
 
+    #[allow(dead_code)]
     fn get_insight_history(
         &mut self,
         context: &opentelemetry::Context,
@@ -79,6 +80,7 @@ impl SqliteInsightDao {
     }
 
     #[cfg(test)]
+    #[allow(dead_code)]
     pub fn from_connection(conn: Arc<Mutex<SqliteConnection>>) -> Self {
         SqliteInsightDao { connection: conn }
     }

src/database/knowledge_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;
 use std::ops::DerefMut;
@@ -230,7 +232,7 @@ impl SqliteKnowledgeDao {
     }
 
     fn deserialize_embedding(bytes: &[u8]) -> Result<Vec<f32>, DbError> {
-        if bytes.len() % 4 != 0 {
+        if !bytes.len().is_multiple_of(4) {
             return Err(DbError::new(DbErrorKind::QueryError));
         }
         Ok(bytes
@@ -535,7 +537,6 @@ impl KnowledgeDao for SqliteKnowledgeDao {
 
             conn.transaction::<(i64, i64), diesel::result::Error, _>(|conn| {
                 use schema::entity_facts::dsl as ef;
-                use schema::entity_photo_links::dsl as epl;
 
                 // 1. Re-point facts where source is subject
                 let facts_updated =

src/database/location_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;
 use serde::Serialize;

src/database/mod.rs

@@ -155,7 +155,9 @@ pub trait FavoriteDao: Sync + Send {
     fn add_favorite(&mut self, user_id: i32, favorite_path: &str) -> Result<usize, DbError>;
     fn remove_favorite(&mut self, user_id: i32, favorite_path: String);
     fn get_favorites(&mut self, user_id: i32) -> Result<Vec<Favorite>, DbError>;
+    #[allow(dead_code)]
     fn update_path(&mut self, old_path: &str, new_path: &str) -> Result<(), DbError>;
+    #[allow(dead_code)]
     fn get_all_paths(&mut self) -> Result<Vec<String>, DbError>;
 }
 
@@ -239,6 +241,7 @@ impl FavoriteDao for SqliteFavoriteDao {
     }
 }
 
+#[allow(dead_code)]
 pub trait ExifDao: Sync + Send {
     fn store_exif(
         &mut self,
@@ -306,6 +309,7 @@ pub trait ExifDao: Sync + Send {
 
     /// Get all photos with GPS coordinates
     /// Returns Vec<(file_path, latitude, longitude, date_taken)>
+    #[allow(clippy::type_complexity)]
     fn get_all_with_gps(
         &mut self,
         context: &opentelemetry::Context,
@@ -680,7 +684,6 @@ impl ExifDao for SqliteExifDao {
         .map_err(|_| DbError::new(DbErrorKind::QueryError))
     }
 
-
     fn get_all_with_gps(
         &mut self,
         context: &opentelemetry::Context,

src/database/preview_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;
 use std::ops::DerefMut;

src/database/search_dao.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 use diesel::prelude::*;
 use diesel::sqlite::SqliteConnection;
 use serde::Serialize;