feat: nightly agentic pre-generation of memory reels

Implement end-to-end nightly pre-generation of memory reels with agentic
scripting that grounds narration in calendar, location, messages, and RAG.

Sections A-E from the plan:

A. Extract produce_reel pipeline core from run_reel_job with
   ScripterMode::Fast/Agentic and progress callbacks.

B. Agentic scripter: factor run_readonly_tool_loop from the insight
   generator, build read-only tool gate, prompt builder with GPS, and
   generate_script_agentic with fallback to fast path.

C. Precomputed reels ledger (SQLite table + DAO), GET /reels/precomputed
   handler with validity gate, GET /reels/by-key/{key}/video streaming,
   and normalize_library_key helper.

D. Nightly scheduler: spawn_pregen_scheduler with configurable hour,
   run_pregen_batch (day/week/month spans), pregen_one with dedup and
   disk-check, secs_until_next_run_hour time math.

E. user_ai_prefs passive mirror table + DAO for param capture in
   create_reel_handler and replay in the scheduler.

Also fixes resolve_library_param signature to take &[Library] and adds
resolve_library_param_state wrapper for AppState callers.

New files: migrations/2026-06-13-000000_add_precomputed_reels/,
  migrations/2026-06-13-000010_add_user_ai_prefs/,
  src/database/precomputed_reel_dao.rs,
  src/database/user_ai_prefs_dao.rs

src/reels/selector.rs

@@ -207,6 +207,7 @@ fn form_photo_beats(
                 date,
                 insight_title: None,
                 insight_summary: None,
+                gps: None,
             }
         })
         .collect()
@@ -255,6 +256,7 @@ pub fn form_beats(
             date: v.created,
             insight_title: None,
             insight_summary: None,
+            gps: None,
         });
     }
 
@@ -334,15 +336,20 @@ fn distinct_years(items: &[memories::MemoryItem], tz: Option<FixedOffset>) -> Ve
     years
 }
 
-/// Background pass: fill each beat's cached insight (title + summary) from its
-/// lead photo, where one exists. Best-effort — a missing or errored lookup
-/// leaves the fields `None` and the scripter narrates from the date alone.
+/// Background pass: fill each beat's cached insight (title + summary) and
+/// GPS coordinates from its lead photo, where one exists. Best-effort — a
+/// missing or errored lookup leaves the fields `None` and the scripter
+/// narrates from the date alone.
 pub fn enrich(
     insight_dao: &Mutex<Box<dyn InsightDao>>,
+    exif_dao: &Mutex<Box<dyn ExifDao>>,
     span_context: &opentelemetry::Context,
     beats: &mut [PlannedBeat],
 ) {
-    let Ok(mut dao) = insight_dao.lock() else {
+    let Ok(mut insight_dao) = insight_dao.lock() else {
+        return;
+    };
+    let Ok(mut exif_dao) = exif_dao.lock() else {
         return;
     };
     for beat in beats.iter_mut() {
@@ -352,10 +359,17 @@ pub fn enrich(
             }
             None => continue,
         };
-        if let Ok(Some(insight)) = dao.get_insight(span_context, &rel_path) {
+        if let Ok(Some(insight)) = insight_dao.get_insight(span_context, &rel_path) {
             beat.insight_title = Some(insight.title);
             beat.insight_summary = Some(insight.summary);
         }
+        // Enrich GPS from EXIF when the lead media is a photo.
+        if let Some(SegmentMedia::Photo { .. }) = beat.media.first()
+            && let Ok(Some(exif)) = exif_dao.get_exif(span_context, &rel_path)
+            && let (Some(lat), Some(lon)) = (exif.gps_latitude, exif.gps_longitude)
+        {
+            beat.gps = Some((lat as f64, lon as f64));
+        }
     }
 }