fix: map markers zoom drift — fixed-size container + center anchor

- All elements (SVG ring + avatar + badge) inside a fixed-size
  container (45x45px) with absolute positioning
- Avatar centered with calculated offset, ring fills container
- Mapbox marker anchor changed from 'bottom' to 'center'
- No more variable margins causing offset drift on zoom

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

src/composables/useMap.js

@@ -192,24 +192,23 @@ export function useMap (deps) {
       const donePct = totalHours > 0 ? Math.min(doneHours / 8, 1) : 0
       const loadColor = loadPct < 0.5 ? '#10b981' : loadPct < 0.75 ? '#f59e0b' : loadPct < 0.9 ? '#f97316' : '#ef4444'
 
-      // SVG ring dimensions
+      // Ring + avatar in a fixed-size container so Mapbox anchor stays consistent
-      const SIZE = 46, STROKE = 3.5, R = (SIZE - STROKE) / 2
+      const PIN = 36, STROKE = 3.5, SIZE = PIN + STROKE * 2 + 2  // ~45px
-      const CIRC = 2 * Math.PI * R
+      const R = (SIZE - STROKE) / 2, CIRC = 2 * Math.PI * R
       const completedJobs = allToday.filter(j => (j.status || '').toLowerCase() === 'completed').length
       const totalJobs = allToday.length
       const completionPct = totalJobs > 0 ? completedJobs / totalJobs : 0
 
-      // Outer wrapper
+      // Fixed-size outer wrapper — Mapbox anchors to this
       const outer = document.createElement('div')
-      outer.style.cssText = 'cursor:pointer;position:relative;'
+      outer.style.cssText = `cursor:pointer;width:${SIZE}px;height:${SIZE}px;position:relative;`
       outer.dataset.techId = tech.id
 
-      // SVG ring (load arc + completion arc)
+      // SVG ring (load arc + completion arc) — fills entire container
       if (totalHours > 0) {
         const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
         svg.setAttribute('width', SIZE); svg.setAttribute('height', SIZE)
         svg.style.cssText = 'position:absolute;top:0;left:0;transform:rotate(-90deg);pointer-events:none;'
-        // Load arc (how full the day is — faded)
         const loadArc = document.createElementNS('http://www.w3.org/2000/svg', 'circle')
         loadArc.setAttribute('cx', SIZE/2); loadArc.setAttribute('cy', SIZE/2); loadArc.setAttribute('r', R)
         loadArc.setAttribute('fill', 'none'); loadArc.setAttribute('stroke', loadColor)
@@ -217,7 +216,6 @@ export function useMap (deps) {
         loadArc.setAttribute('stroke-dasharray', `${CIRC * loadPct} ${CIRC}`)
         loadArc.setAttribute('stroke-linecap', 'round')
         svg.appendChild(loadArc)
-        // Completion arc (jobs done — solid bright)
         if (completionPct > 0) {
           const doneArc = document.createElementNS('http://www.w3.org/2000/svg', 'circle')
           doneArc.setAttribute('cx', SIZE/2); doneArc.setAttribute('cy', SIZE/2); doneArc.setAttribute('r', R)
@@ -230,11 +228,11 @@ export function useMap (deps) {
         outer.appendChild(svg)
       }
 
-      // Avatar circle (centered inside SVG ring)
+      // Avatar circle — absolutely centered in container
       const el = document.createElement('div')
       el.className = 'sb-map-tech-pin'
-      const pad = totalHours > 0 ? STROKE + 1 : 0
+      const offset = (SIZE - PIN) / 2
-      el.style.cssText = `background:${color};border-color:${color};margin:${pad}px;`
+      el.style.cssText = `background:${color};border-color:${color};position:absolute;top:${offset}px;left:${offset}px;width:${PIN}px;height:${PIN}px;`
       el.textContent = initials
       el.title = `${tech.fullName} — ${completedJobs}/${totalJobs} jobs (${doneHours.toFixed(1)}h / ${totalHours.toFixed(1)}h)`
       outer.appendChild(el)
@@ -269,7 +267,7 @@ export function useMap (deps) {
         el.classList.add('sb-map-gps-active')
         el.title += ' (GPS)'
       }
-      const m = new mbgl.Marker({ element: outer, anchor: 'bottom' }).setLngLat(pos).addTo(map)
+      const m = new mbgl.Marker({ element: outer, anchor: 'center' }).setLngLat(pos).addTo(map)
       mapMarkers.value.push(m)
     })
   }