Slow mode replaces the late-evening quarter hours

Slow mode (Home Assistant switch "FlipDot Display Slow mode", dropdown
"FlipDot Display Slow mode interval", web UI Settings) makes the display
change only every 1, 2, 5, 10, 15, 20, 30 or 60 minutes, on the clock, and
powers it off in between: less noise. Nothing else is drawn meanwhile, also
no page changes. It updates at once after boot, the night, the Power switch
and live mode, and when it is switched off. Rules can override it ("show at
once in slow mode"): while their page is shown the display works normally.

Settings layout 7 and schedule layout 4 (older records are converted; they
are stored again once the firmware is marked good, so a rollback still
finds the old ones). Pages in older formats are rewritten in the current
one, in time-boxed steps. /api/status reports old_data_left.

Version 2.15.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/esp32/web/web_page.h

@@ -150,10 +150,12 @@ details{margin-top:10px}summary{cursor:pointer;color:var(--dim);font-size:13px;m
 <section id="t-settings"><div class="card"><h2>Schedule</h2><div class="form">
 <label>Schedule</label><label><input type="checkbox" id="s_en"> on (off: display always on)</label>
 <label>Display on from</label><input type="time" id="s_day">
-<label>Late evening from</label><input type="time" id="s_late">
-<label>Quarter hours</label><label><input type="checkbox" id="s_q"> late evening: only at :00 :15 :30 :45</label>
 <label>Display off from</label><input type="text" id="s_night" placeholder="HH:MM, 24:00 = never" size="8">
 </div></div>
+<div class="card"><h2>Slow mode</h2><div class="form">
+<label>Slow mode</label><label><input type="checkbox" id="s_slow"> on (also the Home Assistant switch)</label>
+<label>Update every</label><select id="s_slowmin"><option value="1">minute</option><option value="2">2 minutes</option><option value="5">5 minutes</option><option value="10">10 minutes</option><option value="15">15 minutes</option><option value="20">20 minutes</option><option value="30">30 minutes</option><option value="60">hour</option></select>
+</div><p class="hint">Fewer flips, less noise: the display only changes at these times (on the clock, 15 minutes = :00 :15 :30 :45) and is switched off in between; the dots keep the image. Page changes wait too, except for rules with "show at once in slow mode".</p></div>
 <div class="card"><h2>Without WiFi</h2><div class="form">
 <label>No WiFi screen</label><label><input type="checkbox" id="c_nw"> show "No WiFi" instead of a dynamic page when WiFi is down</label>
 </div><p class="hint">The backgrounds per time of day (like the yawning Pikachu) are set per page in the Pages tab.</p></div>
@@ -344,6 +346,8 @@ function schedBuild(){if(!sched)return;schedLink();$('sc_en').checked=sched.enab
     'read every',sinp(ru,'interval','number',{style:'width:5em',min:2,max:600}),'s',state,btn('Remove',()=>{sched.rules.splice(i,1);schedDirty=true;schedBuild()},'d')),
    mk('div',{className:'row'},(()=>{const c=mk('input',{type:'checkbox',checked:ru.over_manual!==false});c.onchange=()=>{ru.over_manual=c.checked;schedDirty=true};
     return mk('label',{},c,' also over a page chosen by hand')})(),mk('span',{className:'hint',textContent:'(off: it waits until the chosen page ends: the next block or Back to schedule)'})),
+   mk('div',{className:'row'},(()=>{const c=mk('input',{type:'checkbox',checked:!!ru.over_slow_mode});c.onchange=()=>{ru.over_slow_mode=c.checked;schedDirty=true};
+    return mk('label',{},c,' show at once in slow mode')})(),mk('span',{className:'hint',textContent:'(the display works normally while this page is shown)'})),
    sched.blocks.length?mk('div',{className:'row'},'only in the blocks',...sched.blocks.map(b=>{const c=mk('input',{type:'checkbox',checked:ru._b.includes(b)});
     c.onchange=()=>{ru._b=c.checked?ru._b.concat([b]):ru._b.filter(x=>x!==b);schedDirty=true};return mk('label',{},c,' '+b.start)}),
     mk('span',{className:'hint',textContent:'(none ticked: always)'})):''))});
@@ -351,7 +355,7 @@ function schedBuild(){if(!sched)return;schedLink();$('sc_en').checked=sched.enab
 function scAddBlock(){if(sched.blocks.length>=8){msg('8 blocks at most',true);return}
  sched.blocks.push({start:'12:00',effect:true,items:[{page:settings.page,seconds:30}]});sched.blocks.sort(bySlot);schedDirty=true;schedBuild()}
 function scAddRule(){if(sched.rules.length>=8){msg('8 rules at most',true);return}
- sched.rules.push({entity:'',attribute:'',compare:'eq',value:'',page:settings.page,mode:'while',seconds:30,interval:10,over_manual:true});schedDirty=true;schedBuild()}
+ sched.rules.push({entity:'',attribute:'',compare:'eq',value:'',page:settings.page,mode:'while',seconds:30,interval:10,over_manual:true,over_slow_mode:false});schedDirty=true;schedBuild()}
 async function scSave(){sched.blocks.sort(bySlot);sched=await post('/api/schedule',schedPayload());schedDirty=false;schedBuild();msg('Schedule saved');loadLists()}
 async function backToSchedule(){await post('/api/schedule/back');msg('Back to the schedule');setTimeout(pollStatusOnce,500)}
 async function pollStatusOnce(){try{status=await api('/api/status');$('sc_now').textContent='Showing: '+status.shown+' ('+status.shown_status+')';$('shownnow').textContent=$('sc_now').textContent}catch(e){}}
@@ -635,15 +639,17 @@ async function cycleTest(){clearInterval(testTimer);let n=0;const step=()=>live(
  await step();testTimer=setInterval(step,Math.max(4000,(settings.drive.effect?settings.drive.effect_time:0)+2000))}
 async function stopTest(){clearInterval(testTimer);testTimer=null;await stopLive()}
 // settings
-function fill(){const s=settings;$('s_en').checked=s.schedule.enabled;$('s_day').value=s.schedule.day_start;$('s_late').value=s.schedule.late_start;
- $('s_q').checked=s.schedule.quarter_hours;$('s_night').value=s.schedule.night_start;
+function fill(){const s=settings;$('s_en').checked=s.schedule.enabled;$('s_day').value=s.schedule.day_start;
+ $('s_night').value=s.schedule.night_start;$('s_slow').checked=s.slow_mode.enabled;$('s_slowmin').value=s.slow_mode.minutes;
  $('c_nw').checked=s.clock.no_wifi_screen;$('h_flip').value=s.flip_time;$('h_led').checked=s.status_led;
  $('h_gap').value=s.drive.flip_gap;$('h_pulses').value=s.drive.pulses;$('h_effect').value=s.drive.effect;$('h_efft').value=s.drive.effect_time;$('h_small').checked=s.drive.effect_small_only;$('h_rdots').value=s.refresh.dots;$('h_rimg').value=s.refresh.image;
  $('ha_en').checked=s.home_assistant.enabled;$('ha_host').value=s.home_assistant.host;$('ha_port').value=s.home_assistant.port;$('ha_user').value=s.home_assistant.user;
  $('ha_pass').placeholder=s.home_assistant.password_set?'unchanged':'none';$('ha_url').value=s.home_assistant.api_url;$('ha_plex').value=s.plex_user||'';
  $('ha_token').value='';$('ha_token').placeholder=s.home_assistant.token_set?'unchanged':'none'}
 function collect(){const s=JSON.parse(JSON.stringify(settings));
- Object.assign(s.schedule,{enabled:$('s_en').checked,day_start:$('s_day').value,late_start:$('s_late').value,quarter_hours:$('s_q').checked,night_start:$('s_night').value.trim()});
+ Object.assign(s.schedule,{enabled:$('s_en').checked,day_start:$('s_day').value,night_start:$('s_night').value.trim()});
+ const sm={enabled:$('s_slow').checked,minutes:+$('s_slowmin').value};
+ if(sm.enabled!=settings.slow_mode.enabled||sm.minutes!=settings.slow_mode.minutes)s.slow_mode=sm;else delete s.slow_mode; // HA may have switched it meanwhile
  s.clock={no_wifi_screen:$('c_nw').checked};
  s.flip_time=+$('h_flip').value;s.status_led=$('h_led').checked;
  s.drive={flip_gap:+$('h_gap').value,pulses:+$('h_pulses').value,effect:+$('h_effect').value,effect_time:+$('h_efft').value,effect_small_only:$('h_small').checked};s.refresh={dots:+$('h_rdots').value,image:+$('h_rimg').value};