Refactor project to modularize constants and utilities.

Moved reusable constants and helper functions to dedicated modules for improved maintainability and reusability. Improved build configuration to differentiate output directories for development and production. Enhanced server error handling and added safeguards for disabled web UI scenarios.

app/web/src/utils.js

@@ -0,0 +1,119 @@
+import { kindNames } from './constants.js';
+
+/**
+ * Get human-readable name for a Nostr event kind
+ * @param {number} kind - The event kind number
+ * @returns {string} Human readable kind name
+ */
+export function getKindName(kind) {
+    return kindNames[kind] || `Kind ${kind}`;
+}
+
+/**
+ * Truncate a pubkey for display
+ * @param {string} pubkey - The full pubkey hex string
+ * @returns {string} Truncated pubkey
+ */
+export function truncatePubkey(pubkey) {
+    if (!pubkey) return "unknown";
+    return pubkey.slice(0, 8) + "..." + pubkey.slice(-8);
+}
+
+/**
+ * Truncate content for preview display
+ * @param {string} content - The content to truncate
+ * @param {number} maxLength - Maximum length before truncation
+ * @returns {string} Truncated content
+ */
+export function truncateContent(content, maxLength = 100) {
+    if (!content) return "";
+    return content.length > maxLength
+        ? content.slice(0, maxLength) + "..."
+        : content;
+}
+
+/**
+ * Format a Unix timestamp for display
+ * @param {number} timestamp - Unix timestamp in seconds
+ * @returns {string} Formatted date/time string
+ */
+export function formatTimestamp(timestamp) {
+    if (!timestamp) return "";
+    return new Date(timestamp * 1000).toLocaleString();
+}
+
+/**
+ * Escape HTML special characters to prevent XSS
+ * @param {string} str - String to escape
+ * @returns {string} Escaped string
+ */
+export function escapeHtml(str) {
+    if (!str) return "";
+    return str
+        .replace(/&/g, "&")
+        .replace(/</g, "&lt;")
+        .replace(/>/g, "&gt;")
+        .replace(/"/g, "&quot;")
+        .replace(/'/g, "&#039;");
+}
+
+/**
+ * Convert "about" text to safe HTML with line breaks
+ * @param {string} text - The about text
+ * @returns {string} HTML with line breaks
+ */
+export function aboutToHtml(text) {
+    if (!text) return "";
+    return escapeHtml(text).replace(/\n\n/g, "<br>");
+}
+
+/**
+ * Copy text to clipboard with fallback for older browsers
+ * @param {string} text - Text to copy
+ * @returns {Promise<boolean>} Whether copy succeeded
+ */
+export async function copyToClipboard(text) {
+    try {
+        await navigator.clipboard.writeText(text);
+        return true;
+    } catch (error) {
+        console.error("Failed to copy to clipboard:", error);
+        // Fallback for older browsers
+        try {
+            const textArea = document.createElement("textarea");
+            textArea.value = text;
+            document.body.appendChild(textArea);
+            textArea.select();
+            document.execCommand("copy");
+            document.body.removeChild(textArea);
+            return true;
+        } catch (fallbackError) {
+            console.error("Fallback copy also failed:", fallbackError);
+            return false;
+        }
+    }
+}
+
+/**
+ * Show copy feedback on a button element
+ * @param {HTMLElement} button - The button element
+ * @param {boolean} success - Whether copy succeeded
+ */
+export function showCopyFeedback(button, success = true) {
+    if (!button) return;
+    const originalText = button.textContent;
+    const originalBg = button.style.backgroundColor;
+
+    if (success) {
+        button.textContent = "";
+        button.style.backgroundColor = "#4CAF50";
+    } else {
+        button.textContent = "L";
+        button.style.backgroundColor = "#f44336";
+    }
+
+    setTimeout(() => {
+        button.textContent = originalText;
+        button.style.backgroundColor = originalBg;
+    }, 2000);
+}