Tracing: DAO layer + handler spans on tracing, drop all Context params (#141)

trace_db_call no longer takes an OpenTelemetry Context: it opens a
db.<query_type>.<operation> span (same name via otel.name, same
db.query_type / db.operation attrs) on the caller's ambient tracing span
and runs the DAO body inside it. The cx / ctx / context parameter is gone
from every DAO trait method, impl and call site, and from the helpers and
background drains that only threaded it.

The remaining request-handler spans (files, tags, faces, image, video,
favorites, duplicates, memories) move to #[instrument]; the
Context::current_with_span / with_remote_span_context plumbing is gone, as
is extract_context_from_request (the tracing-actix-web root span covers
it). otel::set_span_attributes replaces BoxedSpan::set_attributes.

Background-job raw spans (thumbnails, video actors) are left for #142.

tests/otel_db_spans.rs pins name, attributes, status and nesting (across
an instrumented spawn); otel_traceparent now uses an #[instrument]
handler. CLAUDE.md documents the tracing conventions.

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

src/cleanup/database_updater.rs

@@ -2,7 +2,6 @@ use crate::database::{ExifDao, FavoriteDao};
 use crate::tags::TagDao;
 use anyhow::Result;
 use log::{error, info};
-use opentelemetry;
 use std::sync::{Arc, Mutex};
 
 pub struct DatabaseUpdater {
@@ -27,13 +26,12 @@ impl DatabaseUpdater {
     /// Update file path across all three database tables
     /// Returns Ok(()) if successful, continues on partial failures but logs errors
     pub fn update_file_path(&mut self, old_path: &str, new_path: &str) -> Result<()> {
-        let context = opentelemetry::Context::current();
         let mut success_count = 0;
         let mut error_count = 0;
 
         // Update tagged_photo table
         if let Ok(mut dao) = self.tag_dao.lock() {
-            match dao.update_photo_name(old_path, new_path, &context) {
+            match dao.update_photo_name(old_path, new_path) {
                 Ok(_) => {
                     info!("Updated tagged_photo: {} -> {}", old_path, new_path);
                     success_count += 1;
@@ -50,7 +48,7 @@ impl DatabaseUpdater {
 
         // Update image_exif table
         if let Ok(mut dao) = self.exif_dao.lock() {
-            match dao.update_file_path(&context, old_path, new_path) {
+            match dao.update_file_path(old_path, new_path) {
                 Ok(_) => {
                     info!("Updated image_exif: {} -> {}", old_path, new_path);
                     success_count += 1;
@@ -102,12 +100,11 @@ impl DatabaseUpdater {
 
     /// Get all file paths from all three database tables
     pub fn get_all_file_paths(&mut self) -> Result<Vec<String>> {
-        let context = opentelemetry::Context::current();
         let mut all_paths = Vec::new();
 
         // Get from tagged_photo
         if let Ok(mut dao) = self.tag_dao.lock() {
-            match dao.get_all_photo_names(&context) {
+            match dao.get_all_photo_names() {
                 Ok(paths) => {
                     info!("Found {} paths in tagged_photo", paths.len());
                     all_paths.extend(paths);
@@ -120,7 +117,7 @@ impl DatabaseUpdater {
 
         // Get from image_exif
         if let Ok(mut dao) = self.exif_dao.lock() {
-            match dao.get_all_file_paths(&context) {
+            match dao.get_all_file_paths() {
                 Ok(paths) => {
                     info!("Found {} paths in image_exif", paths.len());
                     all_paths.extend(paths);