feat: multi-branch template scanning from git repo + manual template selection

- Rewrite template.rs to scan all remote branches via git commands
  (git fetch/branch -r/ls-tree/git show/git archive)
- Add manual template picker dropdown in CreateForm UI
- Remove sentence-transformers/embed.py from Dockerfile (separate container)
- Clean up Gitea API approach, use local git repo instead
- Add chat panel and sidebar layout improvements

src/main.rs

@@ -29,6 +29,15 @@ pub struct Config {
     pub llm: LlmConfig,
     pub server: ServerConfig,
     pub database: DatabaseConfig,
+    #[serde(default)]
+    pub template_repo: Option<TemplateRepoConfig>,
+}
+
+#[derive(Debug, Clone, serde::Deserialize)]
+pub struct TemplateRepoConfig {
+    pub gitea_url: String,
+    pub owner: String,
+    pub repo: String,
 }
 
 #[derive(Debug, Clone, serde::Deserialize)]
@@ -147,6 +156,7 @@ async fn resume_workflows(pool: SqlitePool, agent_mgr: Arc<agent::AgentManager>)
         agent_mgr.send_event(&project_id, agent::AgentEvent::NewRequirement {
             workflow_id,
             requirement,
+            template_id: None,
         }).await;
     }
 }