fix: chat submission and session handling + 37 Playwright tests

- Fix chip auto-submit: use htmx.trigger() instead of native submit
  to bypass browser validation on required field
- Remove required from input (server validates already)
- Fix session_id duplication: use hx-swap-oob to replace single input
- Fix agent context: use background context with 30s timeout instead
  of HTTP request context (prevents premature cancellation)
- Remove redundant close button from header (toggle button handles it)
- Add 83-chat-mascot.test.mjs: 37 tests covering button, panel,
  help card, chips, typed questions, session, Spanish, positioning

internal/chat/handler.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"strings"
+	"time"
 
 	"github.com/juanatsap/cv-site/internal/cache"
 
@@ -132,11 +133,14 @@ func (h *Handler) HandleChat(w http.ResponseWriter, r *http.Request) {
 		sessionID = created.Session.ID()
 	}
 
-	// Run the agent
+	// Run the agent with a dedicated context (not tied to HTTP request lifecycle)
+	agentCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
 	userMsg := genai.NewContentFromText(message, genai.RoleUser)
 
 	var response strings.Builder
-	for event, err := range h.runner.Run(ctx, "visitor", sessionID, userMsg, agent.RunConfig{}) {
+	for event, err := range h.runner.Run(agentCtx, "visitor", sessionID, userMsg, agent.RunConfig{}) {
 		if err != nil {
 			log.Printf("Chat agent error: %v", err)
 			w.Header().Set("Content-Type", "text/html; charset=utf-8")
@@ -168,8 +172,8 @@ func (h *Handler) HandleChat(w http.ResponseWriter, r *http.Request) {
 	}
 	_, _ = fmt.Fprintf(w, `<div class="chat-message chat-agent">%s</div>`, formatResponse(agentText))
 
-	// Hidden input to preserve session ID for next request
-	_, _ = fmt.Fprintf(w, `<input type="hidden" name="session_id" value="%s" form="chat-form"/>`, sessionID)
+	// Update session ID via OOB swap (replaces existing input, avoids duplicates)
+	_, _ = fmt.Fprintf(w, `<input type="hidden" id="chat-session-id" name="session_id" value="%s" form="chat-form" hx-swap-oob="true"/>`, sessionID)
 }
 
 // formatResponse converts basic markdown to HTML for the chat bubble.