add help docs and ?

docs/nodes/Template Match.md

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+# Template Match
+
+Find a template pattern within a larger data field using normalised cross-correlation. The score output shows match quality (1 = perfect match). Equivalent to Gwyddion maskcor.c.
+
+## Inputs
+
+| Name | Type | Required | Description |
+|------|------|----------|-------------|
+| image | DATA_FIELD | Yes | Larger field to search in |
+| template | DATA_FIELD | Yes | Smaller template pattern to find |
+
+## Outputs
+
+| Name | Type | Description |
+|------|------|-------------|
+| score | DATA_FIELD | Normalized cross-correlation score map |
+| detections | IMAGE | Binary mask marking positions above the threshold |
+
+## Controls
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| threshold | FLOAT | 0.8 | Minimum correlation score to mark as a detection (0.0–1.0) |
+
+## Limitations
+
+- The template must be smaller than the image; equal or larger sizes are not supported.
+- Normalized cross-correlation assumes uniform background; strong global gradients reduce detection accuracy.