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/sync.rs

@@ -19,7 +19,8 @@ use crate::archive::indexer::Indexer;
 use crate::archive::schema::ArchiveDocument;
 use crate::brain::conversation::{ContextMessage, ConversationManager};
 use crate::brain::evaluator::{Engagement, Evaluator};
-use crate::brain::responder::Responder;
+use crate::brain::personality::Personality;
+use crate::tools::ToolRegistry;
 use crate::config::Config;
 use crate::context::{self, ResponseContext};
 use crate::conversations::ConversationRegistry;
@@ -30,7 +31,8 @@ pub struct AppState {
     pub config: Arc<Config>,
     pub indexer: Arc<Indexer>,
     pub evaluator: Arc<Evaluator>,
-    pub responder: Arc<Responder>,
+    pub tools: Arc<ToolRegistry>,
+    pub personality: Arc<Personality>,
     pub conversations: Arc<Mutex<ConversationManager>>,
     pub mistral: Arc<mistralai_client::v1::client::Client>,
     pub opensearch: OpenSearch,
@@ -365,41 +367,36 @@ async fn handle_message(
         None
     };
 
-    let response = if state.config.agents.use_conversations_api {
-        state
-            .responder
-            .generate_response_conversations(
-                &body,
-                display_sender,
-                &room_id,
-                &room_name,
-                is_dm,
-                is_spontaneous,
-                &state.mistral,
-                &room,
-                &response_ctx,
-                &state.conversation_registry,
-                image_data_uri.as_deref(),
-                context_hint,
-                event.event_id.clone().into(),
-            )
-            .await
-    } else {
-        state
-            .responder
-            .generate_response(
-                &context,
-                &body,
-                display_sender,
-                &room_name,
-                &members,
-                is_spontaneous,
-                &state.mistral,
-                &room,
-                &response_ctx,
-                image_data_uri.as_deref(),
-            )
-            .await
+    // Generate response via ConversationRegistry (Conversations API path).
+    // The legacy manual chat path has been removed — Conversations API is now mandatory.
+    let input_text = {
+        let tc = crate::time_context::TimeContext::now();
+        let mut header = format!("{}\n[room: {} ({})]", tc.message_line(), room_name, room_id);
+        // TODO: inject memory notes + breadcrumbs here (like the orchestrator does)
+        let user_msg = if is_dm {
+            body.clone()
+        } else {
+            format!("<{}> {}", response_ctx.matrix_user_id, body)
+        };
+        format!("{header}\n{user_msg}")
+    };
+
+    let input = mistralai_client::v1::conversations::ConversationInput::Text(input_text);
+    let conv_result = state
+        .conversation_registry
+        .send_message(&room_id, input, is_dm, &state.mistral, context_hint.as_deref())
+        .await;
+
+    let response = match conv_result {
+        Ok(conv_response) => {
+            // Simple path: extract text (no tool loop for Matrix — tools handled by orchestrator)
+            // TODO: wire full orchestrator + Matrix bridge for tool support
+            conv_response.assistant_text()
+        }
+        Err(e) => {
+            error!("Conversation API failed: {e}");
+            None
+        }
     };
 
     if let Some(text) = response {