feat: add semantic search tool for code symbol indexing and searching

- Implemented a new tool for semantic code search that indexes Rust code symbols (functions, structs, enums, traits, modules) and allows searching by name, concept, or meaning.
- Introduced a symbol index structure with methods for rebuilding the index and searching symbols.
- Added regex patterns for extracting various code symbols from Rust source files.
- Implemented scoring logic for search results based on exact matches, prefix matches, and context relevance.
- Created a web search tool that interacts with a SearXNG instance to fetch documentation and API information based on user queries.
- Added a diff preview overlay for rendering git diff output with color-coded additions and deletions in a TUI interface.

apps/interfaces/tui/src/turn.rs

@@ -61,6 +61,17 @@ pub fn spawn_agent_turn(state: &mut AppStateRest, text: String) {
 
     info!("delegating agent turn to infrastructure engine (model: {})", model);
 
+    let edit_count = state
+        .session_runtime
+        .as_ref()
+        .map(|rt| rt.edit_count)
+        .unwrap_or(0);
+    let consecutive_empty_reviews = state
+        .session_runtime
+        .as_ref()
+        .map(|rt| rt.consecutive_empty_reviews)
+        .unwrap_or(0);
+
     let params = AgentTurnParams {
         messages,
         session_dir,
@@ -71,6 +82,8 @@ pub fn spawn_agent_turn(state: &mut AppStateRest, text: String) {
         api_key,
         model,
         api_base,
+        edit_count,
+        consecutive_empty_reviews,
     };
 
     backend_spawn_agent_turn(params);