refactor: remove legacy responder + agent_ux, add Gitea integration tests

Legacy removal:
- DELETE src/brain/responder.rs (900 lines) — replaced by orchestrator
- DELETE src/agent_ux.rs (184 lines) — UX moved to transport bridges
- EXTRACT chat_blocking() to src/brain/chat.rs (standalone utility)
- sync.rs: uses ConversationRegistry directly (no responder)
- main.rs: holds ToolRegistry + Personality directly (no Responder wrapper)
- research.rs: progress updates via tracing (no AgentProgress)

Gitea integration testing:
- docker-compose: added Gitea service with healthcheck
- bootstrap-gitea.sh: creates admin, org, mirrors 6 real repos from
  src.sunbeam.pt (sol, cli, proxy, storybook, admin-ui, mistralai-client-rs)
- PAT provisioning for SDK testing without Vault
- code_index/gitea.rs: fixed directory listing (direct API calls instead
  of SDK's single-object parser), proper base64 file decoding

New integration tests:
- Gitea: list_repos, get_repo, get_file, directory listing, code indexing
- Web search: SearXNG query with result verification
- Conversation registry: lifecycle + send_message round-trip
- Evaluator: rule matching (DM, own message)
- gRPC bridge: event filtering, tool call mapping, thinking→status

src/main.rs

@@ -1,4 +1,3 @@
-mod agent_ux;
 mod agents;
 mod archive;
 mod brain;
@@ -39,7 +38,6 @@ use conversations::ConversationRegistry;
 use memory::schema::create_index_if_not_exists as create_memory_index;
 use brain::evaluator::Evaluator;
 use brain::personality::Personality;
-use brain::responder::Responder;
 use config::Config;
 use sync::AppState;
 use tools::ToolRegistry;
@@ -212,12 +210,8 @@ async fn main() -> anyhow::Result<()> {
     ));
     let indexer = Arc::new(Indexer::new(os_client.clone(), config.clone()));
     let evaluator = Arc::new(Evaluator::new(config.clone(), system_prompt_text.clone()));
-    let responder = Arc::new(Responder::new(
-        config.clone(),
-        personality,
-        tool_registry,
-        os_client.clone(),
-    ));
+    let tools = tool_registry; // already Arc<ToolRegistry>
+    // personality is already Arc<Personality>
 
     // Start background flush task
     let _flush_handle = indexer.start_flush_task();
@@ -235,7 +229,8 @@ async fn main() -> anyhow::Result<()> {
         config: config.clone(),
         indexer,
         evaluator,
-        responder,
+        tools: tools.clone(),
+        personality,
         conversations,
         agent_registry,
         conversation_registry,
@@ -313,14 +308,14 @@ async fn main() -> anyhow::Result<()> {
             .unwrap_or_default();
         let orch = Arc::new(orchestrator::Orchestrator::new(
             config.clone(),
-            state.responder.tools(),
+            tools.clone(),
             state.mistral.clone(),
             state.conversation_registry.clone(),
             system_prompt_text.clone(),
         ));
         let grpc_state = std::sync::Arc::new(grpc::GrpcState {
             config: config.clone(),
-            tools: state.responder.tools(),
+            tools: tools.clone(),
             store: store.clone(),
             mistral: state.mistral.clone(),
             matrix: Some(matrix_client.clone()),