frontend: rewrite Last Prompt as Prompt History viewer

- status.js: replace loadLastPrompt() with loadPromptHistory() + helpers
  - fetch /prompts with optional source filter, populate dropdown
  - selectPromptEntry() renders metadata bar + collapsible subsections
  - parsePromptSections() splits full_prompt into System/Context/Conversation
  - buildCollapsibleSection() with toggle arrows (▼/▶)
  - copyPromptToClipboard() copies raw text
  - toggleMiddleTruncation() truncates response from middle
  - togglePromptHistoryCollapse() collapses entire section
  - legacy loadLastPrompt() delegates to loadPromptHistory()
- core.js: add promptInterval to polling (10s), visibility resume
  - update switchPromptSource() for 'all' filter + new button IDs
  - update initPromptSourceToggle() default to 'all'
  - declare promptInterval variable

bot/static/js/core.js

@@ -29,6 +29,7 @@ let notificationTimer = null;
 let statusInterval = null;
 let logsInterval = null;
 let argsInterval = null;
+let promptInterval = null;
 
 // Mood emoji mapping
 const MOOD_EMOJIS = {
@@ -211,12 +212,14 @@ function startPolling() {
   if (!statusInterval) statusInterval = setInterval(loadStatus, 10000);
   if (!logsInterval) logsInterval = setInterval(loadLogs, 5000);
   if (!argsInterval) argsInterval = setInterval(loadActiveArguments, 5000);
+  if (!promptInterval) promptInterval = setInterval(loadPromptHistory, 10000);
 }
 
 function stopPolling() {
   clearInterval(statusInterval); statusInterval = null;
   clearInterval(logsInterval); logsInterval = null;
   clearInterval(argsInterval); argsInterval = null;
+  clearInterval(promptInterval); promptInterval = null;
 }
 
 // ============================================================================
@@ -248,7 +251,7 @@ function initVisibilityPolling() {
       stopPolling();
       console.log('⏸ Tab hidden — polling paused');
     } else {
-      loadStatus(); loadLogs(); loadActiveArguments();
+      loadStatus(); loadLogs(); loadActiveArguments(); loadPromptHistory();
       startPolling();
       console.log('▶️ Tab visible — polling resumed');
     }
@@ -296,9 +299,11 @@ function initModalAccessibility() {
 }
 
 function initPromptSourceToggle() {
-  const saved = localStorage.getItem('miku-prompt-source') || 'cat';
+  const saved = localStorage.getItem('miku-prompt-source') || 'all';
   document.querySelectorAll('.prompt-source-btn').forEach(btn => btn.classList.remove('active'));
-  document.getElementById(`prompt-src-${saved}`).classList.add('active');
+  const btnId = saved === 'all' ? 'prompt-src-all' : `prompt-src-${saved}`;
+  const btn = document.getElementById(btnId);
+  if (btn) btn.classList.add('active');
 }
 
 function initLogsScrollDetection() {
@@ -360,8 +365,10 @@ async function loadLogs() {
 function switchPromptSource(source) {
   localStorage.setItem('miku-prompt-source', source);
   document.querySelectorAll('.prompt-source-btn').forEach(btn => btn.classList.remove('active'));
-  document.getElementById(`prompt-src-${source}`).classList.add('active');
-  loadLastPrompt();
+  const btnId = source === 'all' ? 'prompt-src-all' : `prompt-src-${source}`;
+  const btn = document.getElementById(btnId);
+  if (btn) btn.classList.add('active');
+  loadPromptHistory();
 }
 
 // ============================================================================