feat: add backend pagination support for infinite scroll in issues and pulls

Update ListAllIssues and ListAllPullRequests to accept state and page
parameters, returning paginated results (20 per page) with HasMore
metadata. ListIssues and ListPulls handlers now read page, org, and
state query params; HTMX requests for page > 1 return only card HTML
fragments for seamless infinite scroll. Both templates extract a
reusable "cards" block and pulls.html gains a scroll sentinel matching
the existing issues.html pattern. Filter changes reset to page 1.

Closes leeworks-agents/gitea-mobile#32

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/handlers/handlers.go

@@ -239,6 +239,10 @@ func (h *Handler) ListIssues(w http.ResponseWriter, r *http.Request) {
 	if selectedState == "" {
 		selectedState = "open"
 	}
+	page, _ := strconv.Atoi(r.URL.Query().Get("page"))
+	if page < 1 {
+		page = 1
+	}
 
 	data := issuesData{
 		Orgs:          orgNames,
@@ -255,15 +259,38 @@ func (h *Handler) ListIssues(w http.ResponseWriter, r *http.Request) {
 			queryOrgs = []string{selectedOrg}
 		}
 
-		issues, err := h.Client.ListAllIssues(r.Context(), token, queryOrgs)
+		result, err := h.Client.ListAllIssues(r.Context(), token, queryOrgs, selectedState, page)
 		if err != nil {
 			slog.Error("failed to list issues", "error", err)
 			data.Error = "Error loading issues."
 		} else {
-			data.Issues = issues
+			data.Issues = result.Issues
+			data.HasMore = result.HasMore
+			if result.HasMore {
+				data.NextPage = page + 1
+			}
 		}
 	}
 
+	// For HTMX infinite-scroll requests (page > 1), return only the card fragment.
+	if isHTMX(r) && page > 1 {
+		tmpl, err := template.ParseFiles("internal/templates/issues.html")
+		if err != nil {
+			slog.Error("failed to parse issues template", "error", err)
+			http.Error(w, "template error", http.StatusInternalServerError)
+			return
+		}
+		var buf strings.Builder
+		if err := tmpl.ExecuteTemplate(&buf, "cards", data); err != nil {
+			slog.Error("failed to execute issues cards template", "error", err)
+			http.Error(w, "template error", http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		fmt.Fprint(w, buf.String())
+		return
+	}
+
 	tmpl, err := template.ParseFiles("internal/templates/issues.html")
 	if err != nil {
 		slog.Error("failed to parse issues template", "error", err)
@@ -290,10 +317,16 @@ func (h *Handler) ListPulls(w http.ResponseWriter, r *http.Request) {
 		Pulls       []giteaclient.PullRequest
 		Orgs        []string
 		SelectedOrg string
+		HasMore     bool
+		NextPage    int
 		Error       string
 	}
 
 	selectedOrg := r.URL.Query().Get("org")
+	page, _ := strconv.Atoi(r.URL.Query().Get("page"))
+	if page < 1 {
+		page = 1
+	}
 
 	data := pullsData{
 		Orgs:        orgNames,
@@ -308,15 +341,38 @@ func (h *Handler) ListPulls(w http.ResponseWriter, r *http.Request) {
 			queryOrgs = []string{selectedOrg}
 		}
 
-		prs, err := h.Client.ListAllPullRequests(r.Context(), token, queryOrgs)
+		result, err := h.Client.ListAllPullRequests(r.Context(), token, queryOrgs, "open", page)
 		if err != nil {
 			slog.Error("failed to list pull requests", "error", err)
 			data.Error = "Error loading pull requests."
 		} else {
-			data.Pulls = prs
+			data.Pulls = result.Pulls
+			data.HasMore = result.HasMore
+			if result.HasMore {
+				data.NextPage = page + 1
+			}
 		}
 	}
 
+	// For HTMX infinite-scroll requests (page > 1), return only the card fragment.
+	if isHTMX(r) && page > 1 {
+		tmpl, err := template.ParseFiles("internal/templates/pulls.html")
+		if err != nil {
+			slog.Error("failed to parse pulls template", "error", err)
+			http.Error(w, "template error", http.StatusInternalServerError)
+			return
+		}
+		var buf strings.Builder
+		if err := tmpl.ExecuteTemplate(&buf, "cards", data); err != nil {
+			slog.Error("failed to execute pulls cards template", "error", err)
+			http.Error(w, "template error", http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		fmt.Fprint(w, buf.String())
+		return
+	}
+
 	tmpl, err := template.ParseFiles("internal/templates/pulls.html")
 	if err != nil {
 		slog.Error("failed to parse pulls template", "error", err)