feat: delete traffic targets and LLM task conversations from UI

Add delete controls to the Traffic and LLM Records pages so users can
purge recorded data without hand-editing the data volume.

Traffic page:
- Host target picker (Popover with checkboxes + select-all toggle)
- Exact-match batch delete for multiple hosts (DELETE /api/traffic/hosts)
- Substring delete for the host-filter input (DELETE /api/traffic?host=)
- Orphaned content-addressed blob garbage collection after deletes
- Distinct-hosts endpoint (GET /api/traffic/hosts) for the picker

LLM Records page:
- Task picker dropdown (distinct task_id + record counts)
- Per-task delete (DELETE /api/llm/records?task=)

Other:
- Add /dist/ to .gitignore (build artifact)
- Extend traffic_test.go with DeleteHost, DeleteHostsExact, Hosts tests
- Fix Popover render bug (replace ScrollArea that broke height calc)
- Remove fade/zoom animation on the host picker Popover

server/commands.go

@@ -3,6 +3,7 @@ package server
 import (
 	"net/http"
 	"strconv"
+	"strings"
 )
 
 // pgListCommands returns tool executions (any tool) from the activity table.
@@ -34,8 +35,9 @@ func (s *Server) pgListLLMRecords(w http.ResponseWriter, r *http.Request) {
 	size := atoiDefault(q.Get("size"), 50)
 	model := q.Get("model")
 	session := q.Get("session")
+	task := q.Get("task")
 
-	records, total, err := s.m.PG().ListLLMRecords(model, session, page, size)
+	records, total, err := s.m.PG().ListLLMRecords(model, session, task, page, size)
 	if err != nil {
 		writeErr(w, 500, err.Error())
 		return
@@ -43,6 +45,33 @@ func (s *Server) pgListLLMRecords(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, 200, map[string]any{"records": records, "total": total})
 }
 
+// pgLLMTasks returns distinct recorded tasks with counts, for the page's task
+// picker (pick a task → filter the list, then delete its conversations).
+func (s *Server) pgLLMTasks(w http.ResponseWriter, r *http.Request) {
+	tasks, err := s.m.PG().LLMTasks()
+	if err != nil {
+		writeErr(w, 500, err.Error())
+		return
+	}
+	writeJSON(w, 200, map[string]any{"tasks": tasks})
+}
+
+// pgDeleteLLMRecords removes all LLM records for one exact task_id (the same
+// match the task picker uses). Empty task → 400. Returns rows deleted.
+func (s *Server) pgDeleteLLMRecords(w http.ResponseWriter, r *http.Request) {
+	task := strings.TrimSpace(r.URL.Query().Get("task"))
+	if task == "" {
+		writeErr(w, 400, "missing task")
+		return
+	}
+	n, err := s.m.PG().DeleteLLMRecords(task)
+	if err != nil {
+		writeErr(w, 500, err.Error())
+		return
+	}
+	writeJSON(w, 200, map[string]any{"deleted": n})
+}
+
 // pgGetLLMRecord returns a single LLM record with full request/response bodies.
 func (s *Server) pgGetLLMRecord(w http.ResponseWriter, r *http.Request) {
 	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)