refactor: compile the crate once — main.rs uses the library

main.rs re-declared nearly every module (`mod ai; mod database; …`)
that lib.rs also declared, so the ~100k-line crate compiled twice in
every build (lib for the src/bin tools, bin for the server) and the
test suite ran most tests twice. watcher.rs even reached into the lib
copy via `image_api::` from inside the bin copy.

The six bin-only modules (backfill, handlers, hls_stats, knowledge,
reels, watcher) move into lib.rs; main.rs keeps only startup wiring
over `use image_api::…`. A few items main calls become `pub`, and the
dead_code allowances that only existed because each copy saw half the
callers are gone. CLAUDE.md says not to reintroduce `mod` in main.rs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CLAUDE.md

@@ -84,7 +84,7 @@ cargo run --bin create_user -- <username> <password>
 ### Core Components
 
 **Layered Architecture:**
-- **Startup wiring** (`main.rs`): only ~350 lines — env load, migrations, AppState, route registration, server bind. Background jobs are kicked off here but defined elsewhere.
+- **Startup wiring** (`main.rs`): only ~350 lines — env load, migrations, AppState, route registration, server bind. Background jobs are kicked off here but defined elsewhere. Every module lives in the `image_api` library (`lib.rs`); `main.rs` and the `src/bin` tools only `use image_api::…`. Never add `mod` declarations to `main.rs` — that compiles the module a second time (doubling release builds and running its tests twice). Anything `main.rs` calls must be `pub`.
 - **HTTP Layer** (`handlers/{image,video,favorites}.rs`, `files.rs`, `tags.rs`, `faces.rs`, `memories.rs`, `ai/handlers.rs`): the route handlers, grouped by domain.
 - **Background loops** (`watcher.rs`): the file-watcher tick (`watch_files`, `process_new_files`) and the orphaned-playlist cleanup (`cleanup_orphaned_playlists`). Per-tick drains are factored into `backfill.rs` (`backfill_unhashed_backlog`, `backfill_missing_date_taken`, `backfill_missing_content_hashes`, `process_face_backlog`, `build_face_candidates`).
 - **Thumbnails** (`thumbnails.rs`): generation pipeline + the `IMAGE_GAUGE` / `VIDEO_GAUGE` Prometheus metrics.

src/ai/insight_generator.rs

@@ -4517,10 +4517,6 @@ Return ONLY the summary, nothing else."#,
     ///
     /// Calls `execute_tool` with empty file/image context; enabled tools
     /// never read those fields.
-    ///
-    /// Only used by the `reels` module (compiled in `main.rs`, not `lib.rs`),
-    /// so the `#[allow(dead_code)]` suppresses the lib-target warning.
-    #[allow(dead_code)]
     pub(crate) async fn run_readonly_tool_loop(
         &self,
         backend: &ResolvedBackend,

src/ai/local_llm.rs

@@ -13,9 +13,6 @@
 //! is request-scoped and stays in `ResolvedBackend`. This is only the
 //! local stack: embeddings and offline single-shot generation.
 
-// Constructed by binaries, not the server — dead code from main.rs's view.
-#![allow(dead_code)]
-
 use std::sync::Arc;
 
 use anyhow::Result;

src/database/reconcile.rs

@@ -26,11 +26,6 @@
 //! The pass operates on the database alone — no filesystem access —
 //! so it doesn't need the library availability gate.
 
-// The lib doesn't call into this module directly — the watcher (in the
-// bin) does. Dead-code analysis at the lib level can't see that, so
-// suppress at the module level. Tests still exercise every function.
-#![allow(dead_code)]
-
 use diesel::prelude::*;
 use diesel::sql_query;
 use diesel::sqlite::SqliteConnection;

src/files.rs

@@ -1342,8 +1342,7 @@ pub struct RealFileSystem {
 }
 
 impl RealFileSystem {
-    #[allow(dead_code)] // Used in main.rs binary and tests
-    pub(crate) fn new(base_path: String) -> RealFileSystem {
+    pub fn new(base_path: String) -> RealFileSystem {
         RealFileSystem { base_path }
     }
 }

src/lib.rs

@@ -5,6 +5,7 @@ extern crate diesel;
 
 pub mod ai;
 pub mod auth;
+pub mod backfill;
 pub mod bin_progress;
 pub mod camera_tz;
 pub mod cleanup;
@@ -25,6 +26,9 @@ pub mod file_types;
 pub mod filename_audit;
 pub mod files;
 pub mod geo;
+pub mod handlers;
+pub mod hls_stats;
+pub mod knowledge;
 pub mod libraries;
 pub mod library_maintenance;
 pub mod memories;
@@ -33,6 +37,7 @@ pub mod parsers;
 pub mod perceptual_hash;
 pub mod personas;
 pub mod prefs;
+pub mod reels;
 pub mod service;
 pub mod state;
 pub mod tags;
@@ -42,6 +47,7 @@ pub mod thumbnails;
 pub mod unified_search;
 pub mod utils;
 pub mod video;
+pub mod watcher;
 
 // Re-export commonly used types
 pub use data::{Claims, ThumbnailRequest};

src/main.rs

@@ -1,9 +1,7 @@
+//! The server binary. Everything it runs lives in the `image_api`
+//! library so the crate compiles once, shared with the `src/bin` tools.
 #![allow(clippy::too_many_arguments)]
 
-#[macro_use]
-extern crate diesel;
-extern crate rayon;
-
 use actix_web::web::Data;
 use actix_web_prom::PrometheusMetricsBuilder;
 use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
@@ -18,62 +16,16 @@ use actix_web::{App, HttpResponse, HttpServer, middleware, web};
 use diesel::sqlite::Sqlite;
 use std::error::Error;
 
-use crate::ai::InsightGenerator;
-use crate::auth::login;
-use crate::data::*;
-use crate::database::*;
-use crate::files::{RealFileSystem, move_file};
-use crate::service::ServiceBuilder;
-use crate::state::AppState;
-use crate::tags::*;
+use image_api::ai::InsightGenerator;
+use image_api::auth::login;
+use image_api::database::*;
+use image_api::files::{RealFileSystem, move_file};
+use image_api::service::ServiceBuilder;
+use image_api::state::AppState;
+use image_api::tags::*;
+use image_api::*;
 use log::{error, info};
 
-mod ai;
-mod auth;
-mod backfill;
-// Display-zone helpers land in the read-side cutover (#119/#120); the
-// binary's private copy of this module doesn't use them yet.
-#[allow(dead_code)]
-mod camera_tz;
-mod clip_search;
-mod clip_watch;
-mod content_hash;
-mod data;
-mod database;
-mod date_resolver;
-mod date_view;
-mod duplicates;
-mod error;
-mod exif;
-mod face_watch;
-mod faces;
-mod file_scan;
-mod file_types;
-mod files;
-mod geo;
-mod handlers;
-mod hls_stats;
-mod libraries;
-mod library_maintenance;
-mod perceptual_hash;
-mod state;
-mod tags;
-mod thumbnails;
-mod unified_search;
-mod utils;
-mod video;
-mod watcher;
-
-mod knowledge;
-mod memories;
-mod otel;
-mod personas;
-mod prefs;
-mod reels;
-mod service;
-#[cfg(test)]
-mod testhelpers;
-
 pub const MIGRATIONS: EmbeddedMigrations = embed_migrations!();
 
 fn main() -> std::io::Result<()> {
@@ -85,7 +37,7 @@ fn main() -> std::io::Result<()> {
 
     // Recover orphaned insight generation jobs from a previous crash.
     {
-        use crate::database::{InsightGenerationJobDao, SqliteInsightGenerationJobDao};
+        use image_api::database::{InsightGenerationJobDao, SqliteInsightGenerationJobDao};
         let mut dao = SqliteInsightGenerationJobDao::new();
         match dao.recover_orphaned_jobs() {
             Ok(n) if n > 0 => {
@@ -228,9 +180,9 @@ fn main() -> std::io::Result<()> {
 
         // Spawn background job to generate daily conversation summaries
         {
-            use crate::ai::generate_daily_summaries;
-            use crate::database::{DailySummaryDao, SqliteDailySummaryDao};
             use chrono::NaiveDate;
+            use image_api::ai::generate_daily_summaries;
+            use image_api::database::{DailySummaryDao, SqliteDailySummaryDao};
 
             // Configure date range for summary generation
             // Default: August 2024 ±30 days (July 1 - September 30, 2024)
@@ -453,7 +405,7 @@ fn main() -> std::io::Result<()> {
                     Box::new(database::SqlitePersonaDao::new()),
                 )))
                 .app_data::<Data<Mutex<faces::SqliteFaceDao>>>(Data::new(Mutex::new(face_dao)))
-                .app_data::<Data<crate::ai::face_client::FaceClient>>(Data::new(
+                .app_data::<Data<image_api::ai::face_client::FaceClient>>(Data::new(
                     app_data.face_client.clone(),
                 ))
                 .app_data(mp::form::MultipartFormConfig::default().total_limit(1024 * 1024 * 1024)) // 1GB upload limit

src/reels/mod.rs

@@ -1045,7 +1045,7 @@ fn load_pregen_params(app_state: &AppState) -> (String, Option<String>, String)
 }
 
 /// Spawn the nightly pre-generation scheduler. Runs behind `REEL_PREGEN_ENABLED`.
-pub(crate) async fn spawn_pregen_scheduler(app_state: web::Data<AppState>) {
+pub async fn spawn_pregen_scheduler(app_state: web::Data<AppState>) {
     if std::env::var("REEL_PREGEN_ENABLED").ok() != Some("1".to_string()) {
         log::info!("Reel pre-generation scheduler disabled (REEL_PREGEN_ENABLED != 1)");
         return;
@@ -1270,7 +1270,7 @@ fn reel_cache_max_age_secs() -> u64 {
 /// Spawn the periodic on-disk reel-cache sweeper. Runs independently of the
 /// pre-gen scheduler because the on-demand cache grows whether or not pre-gen
 /// is enabled. Disable with `REEL_CACHE_SWEEP_ENABLED=0`.
-pub(crate) async fn spawn_reel_cache_sweeper(app_state: web::Data<AppState>) {
+pub async fn spawn_reel_cache_sweeper(app_state: web::Data<AppState>) {
     if std::env::var("REEL_CACHE_SWEEP_ENABLED").ok().as_deref() == Some("0") {
         log::info!("Reel cache sweeper disabled (REEL_CACHE_SWEEP_ENABLED=0)");
         return;

src/watcher.rs

@@ -628,11 +628,11 @@ pub fn watch_files(
             // See database::reconcile and CLAUDE.md "Multi-library data
             // model" for the rules.
             {
-                let mut conn = image_api::database::connect();
+                let mut conn = crate::database::connect();
                 if is_full_scan {
                     library_maintenance::refresh_planner_stats(&mut conn);
                 }
-                let _ = image_api::database::reconcile::run(&mut conn);
+                let _ = crate::database::reconcile::run(&mut conn);
 
                 // Back-ref refresh: hash-keyed rows whose
                 // (library_id, rel_path) tuple no longer matches any
@@ -721,7 +721,7 @@ pub fn process_new_files(
     // filters. See `file_scan` for why exclusion has to happen at WalkDir
     // time (filter_entry) rather than at face-detect time.
     let files: Vec<(PathBuf, String)> =
-        image_api::file_scan::enumerate_indexable_files(base_path, excluded_dirs, modified_since);
+        crate::file_scan::enumerate_indexable_files(base_path, excluded_dirs, modified_since);
 
     if files.is_empty() {
         debug!("No files to process");