fix: carry all unit data into + Inserat prefill

When clicking + Inserat in UnitStructurePanel, the new listing form
now pre-populates: floor label, fit-out standard, parking, ceiling
height, Mieterausbaubeitrag, Teilbar toggle, min lettable sqm, and
availability date from the unit and its parent property.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/supply/UnitStructurePanel.tsx

@@ -143,21 +143,30 @@ export function UnitStructurePanel({ p }: { p: Property }) {
                         </Box>
                       </Tooltip>
 
-                      {/* Inline min-unit editor */}
-                      {editingFlexUnit === u.id && (
+                      {/* Inline min-unit editor — show when actively editing OR when teilbar is on but min sqm not set */}
+                      {(editingFlexUnit === u.id || (u.isFlexible && !u.minLettableSqm)) && (
                         <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                           <TextField
                             size="small"
                             type="number"
-                            placeholder="Min m²"
+                            autoFocus={!u.minLettableSqm}
+                            placeholder="Min m² *"
                             value={flexDraft[u.id] ?? ''}
                             onChange={e => setFlexDraft(d => ({ ...d, [u.id]: parseInt(e.target.value) || undefined }))}
-                            sx={{ width: 72, '& .MuiInputBase-input': { fontSize: '0.68rem', py: 0.375, px: 0.75 } }}
+                            error={!flexDraft[u.id] && u.isFlexible && !u.minLettableSqm}
+                            sx={{
+                              width: 80,
+                              '& .MuiInputBase-input': { fontSize: '0.68rem', py: 0.375, px: 0.75 },
+                              '& .MuiOutlinedInput-root': {
+                                '& fieldset': { borderColor: (!flexDraft[u.id] && u.isFlexible && !u.minLettableSqm) ? '#ef4444' : undefined },
+                              },
+                            }}
                             slotProps={{ htmlInput: { min: 10, max: u.areaSqm, step: 10 } }}
                           />
                           <Button
                             size="small"
                             variant="contained"
+                            disabled={!flexDraft[u.id]}
                             sx={{ fontSize: '0.58rem', py: 0.25, px: 0.75, minWidth: 0, bgcolor: '#1d4ed8', '&:hover': { bgcolor: '#1e40af' } }}
                             onClick={() => {
                               updateUnit.mutate({ unitId: u.id, data: { isFlexible: true, minLettableSqm: flexDraft[u.id] } })
@@ -166,14 +175,16 @@ export function UnitStructurePanel({ p }: { p: Property }) {
                           >
                             ✓
                           </Button>
-                          <Button
-                            size="small"
-                            variant="text"
-                            sx={{ fontSize: '0.58rem', py: 0.25, px: 0.5, minWidth: 0, color: DS_TEXT.muted }}
-                            onClick={() => setEditingFlexUnit(null)}
-                          >
-                            ✕
-                          </Button>
+                          {editingFlexUnit === u.id && u.minLettableSqm && (
+                            <Button
+                              size="small"
+                              variant="text"
+                              sx={{ fontSize: '0.58rem', py: 0.25, px: 0.5, minWidth: 0, color: DS_TEXT.muted }}
+                              onClick={() => setEditingFlexUnit(null)}
+                            >
+                              ✕
+                            </Button>
+                          )}
                         </Box>
                       )}
 
@@ -193,6 +204,14 @@ export function UnitStructurePanel({ p }: { p: Property }) {
                               rentPricePerSqm: u.rentPricePerSqm ?? p.rentPricePerSqm,
                               unitLabel: u.unitLabel,
                               propertyId: p.id,
+                              floor: floorLabel(u),
+                              fitOut: p.hardFacts?.fitOut,
+                              parking: p.hardFacts?.parking,
+                              ceilingHeight: p.hardFacts?.ceilingHeightM,
+                              mieterausbaubeitragPerSqm: p.hardFacts?.mieterausbaubeitragPerSqm,
+                              isFlexible: u.isFlexible,
+                              minLettableSqm: u.minLettableSqm,
+                              availableFrom: u.listing?.availableFrom ?? p.availabilityDate,
                             },
                           },
                         })}