Add alignment state indicator and pluggable data sources

- AlignmentThresholds dataclass + VisionEngine.__init__ for injection
- alignment_state computed per snapshot (ready/aligning/fault)
- MonitorPlot circle/vector/legend driven by state color
- Status dot + label moved into POSITION VISUALIZATION panel header
- CsvSessionSource + DemoSource pluggable DataSource layer
- Synthetic DATA/ready/ and DATA/aligning/ sessions for visual testing
- Fix CAM 3 label placement (below circle, not above)

DATA/0709/R20709P0.CSV

@@ -0,0 +1,55 @@
+# saved_on,DATA
+# master_file,R20709P0.CSV
+# remote_begin,BEGIN_REMOTE_CSV SOURCE=BOARD_REMOTE SPI=2 BIT=4 POINTS=45 MODE=ORDINARY STATUS=ERROR
+# source,BOARD_REMOTE
+# spi,SPI2
+# tick_ms,191624
+# bit,4
+# edge_mode,ORDINARY
+# points,45
+x,y
+38,5
+271,5
+288,5
+66,22
+142,23
+129,27
+179,36
+58,39
+289,52
+136,60
+136,68
+54,69
+318,80
+146,81
+122,84
+108,128
+67,135
+105,136
+80,140
+68,154
+284,154
+235,162
+2,171
+108,176
+53,182
+21,184
+158,187
+19,190
+126,190
+287,209
+91,212
+48,217
+283,219
+76,221
+83,227
+259,251
+110,260
+38,276
+225,279
+77,280
+299,283
+55,284
+145,310
+155,314
+235,319