feat: add entity-relationship knowledge memory to agentic insights

Implements persistent cross-photo knowledge memory so the agentic
insight loop can learn and recall facts about people, places, and
events across the photo collection.

Changes:
- photo_insights: drop UNIQUE(file_path) + INSERT OR REPLACE, replace
  with append-only rows + is_current flag for insight history retention
- New tables: entities, entity_facts, entity_photo_links with FK
  constraints and confidence scoring
- KnowledgeDao trait + SqliteKnowledgeDao with upsert, merge, and
  corroboration (confidence +0.1 on duplicate fact detection)
- Four new agent tools: recall_entities, recall_facts_for_photo,
  store_entity, store_fact (with object_entity_id FK support)
- Cameron entity auto-seeded with stable ID injected into system prompt
- Pre-run photo link clearing + post-loop source_insight_id backfill
- Audit REST API: GET/PATCH/DELETE /knowledge/entities/{id},
  POST /knowledge/entities/merge, GET/PATCH/DELETE /knowledge/facts/{id},
  GET /knowledge/recent

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/state.rs

@@ -1,8 +1,8 @@
 use crate::ai::{InsightGenerator, OllamaClient, SmsApiClient};
 use crate::database::{
-    CalendarEventDao, DailySummaryDao, ExifDao, InsightDao, LocationHistoryDao, SearchHistoryDao,
-    SqliteCalendarEventDao, SqliteDailySummaryDao, SqliteExifDao, SqliteInsightDao,
-    SqliteLocationHistoryDao, SqliteSearchHistoryDao,
+    CalendarEventDao, DailySummaryDao, ExifDao, InsightDao, KnowledgeDao, LocationHistoryDao,
+    SearchHistoryDao, SqliteCalendarEventDao, SqliteDailySummaryDao, SqliteExifDao,
+    SqliteInsightDao, SqliteKnowledgeDao, SqliteLocationHistoryDao, SqliteSearchHistoryDao,
 };
 use crate::database::{PreviewDao, SqlitePreviewDao};
 use crate::tags::{SqliteTagDao, TagDao};
@@ -119,6 +119,8 @@ impl Default for AppState {
             Arc::new(Mutex::new(Box::new(SqliteSearchHistoryDao::new())));
         let tag_dao: Arc<Mutex<Box<dyn TagDao>>> =
             Arc::new(Mutex::new(Box::new(SqliteTagDao::default())));
+        let knowledge_dao: Arc<Mutex<Box<dyn KnowledgeDao>>> =
+            Arc::new(Mutex::new(Box::new(SqliteKnowledgeDao::new())));
 
         // Load base path
         let base_path = env::var("BASE_PATH").expect("BASE_PATH was not set in the env");
@@ -134,6 +136,7 @@ impl Default for AppState {
             location_dao.clone(),
             search_dao.clone(),
             tag_dao.clone(),
+            knowledge_dao,
             base_path.clone(),
         );
 
@@ -200,6 +203,8 @@ impl AppState {
             Arc::new(Mutex::new(Box::new(SqliteSearchHistoryDao::new())));
         let tag_dao: Arc<Mutex<Box<dyn TagDao>>> =
             Arc::new(Mutex::new(Box::new(SqliteTagDao::default())));
+        let knowledge_dao: Arc<Mutex<Box<dyn KnowledgeDao>>> =
+            Arc::new(Mutex::new(Box::new(SqliteKnowledgeDao::new())));
 
         // Initialize test InsightGenerator with all data sources
         let base_path_str = base_path.to_string_lossy().to_string();
@@ -213,6 +218,7 @@ impl AppState {
             location_dao.clone(),
             search_dao.clone(),
             tag_dao.clone(),
+            knowledge_dao,
             base_path_str.clone(),
         );