Feat/Sketch: associative pattern tools with independent directions and Flip/Center controls (#1601)

Thanks @Karl-VonRichter.

docs/book/src/guide/files.md

@@ -91,6 +91,9 @@ in the file). It opens designs of every older format and upgrades them as they o
 from a newer version asks you to update instead of being guessed at. Development (nightly) builds
 save a format number no release reads yet.
 
+Sketch patterns retain their live direction-line references and placement settings when saved.
+Older patterns keep their fixed vector directions and original placement defaults.
+
 Upgrading keeps what a design meant. Designs keep recorded body transfers, explicit 3D curve coordinate
 spaces and certified face bindings, alongside semantic configuration styles, associative
 free-form offsets and cylindrical emboss selections. Older ownership maps, geometry and

docs/sketch-patterns.md

@@ -0,0 +1,72 @@
+# Sketch patterns
+
+While editing a sketch, use the **PATTERN** toolbar group for **Mirror**,
+**Rectangular Pattern** or **Circular Pattern**. On a narrow window the group
+collapses to a dropdown. Select several curves before starting a tool, or add
+them to its **Entities** input. Each tool previews the result before **OK**;
+**Escape** cancels it.
+
+- **Mirror:** select the source geometry and a straight sketch **Mirror line**.
+  Symmetry constraints keep the copies linked to the source and mirror line.
+- **Rectangular Pattern:** pick **Direction** and optionally **Direction 2**.
+  Each accepts a straight sketch line or an origin axis in the sketch plane.
+  The lines can meet at any angle. Each direction has its own column with a line
+  picker, quantity, spacing and two icon buttons: **Flip direction** and **Center**.
+  Without Center, copies extend from the original along the line from start to end;
+  Flip reverses that direction. Center distributes copies on both sides while the
+  original remains fixed. Quantities are totals including the original: 3 means
+  one copy on either side; 4 means two on one side and one on the other. Flip swaps
+  which side receives the extra copy. Both controls are independent for each direction.
+  Negative spacing reverses the chosen direction. With no direction selected, the first uses sketch X
+  and the second is perpendicular to the first. A second quantity of 1 makes
+  a single row. Picked sketch lines remain live references as they change.
+- **Circular Pattern:** pick a **Center** point (or click empty sketch space),
+  then set **Quantity** and **Total angle**. A full turn distributes instances
+  evenly without duplicating the first; a partial turn includes both endpoints.
+  **Center** places copies on both angular sides of the original. **Flip direction**
+  reverses rotation and chooses the extra side for even totals. For six total holes
+  over 90 degrees, the spacing is 18 degrees: the original stays at 0 degrees, with
+  copies at +18, -18, +36, -36 and +54 degrees. Flip moves the last copy to -54 degrees.
+  Five holes over 90 degrees use 22.5-degree spacing and extend 45 degrees either side.
+  Without Center, a positive angle proceeds counterclockwise from the original;
+  Flip reverses it.
+
+Quantities include the original. Edit the original lines or their dimensions
+to update their copies. Right-click a rectangular or circular pattern instance
+and choose **Edit Sketch Pattern**, or double-click its pattern constraint badge,
+to change the quantities, spacing, directions or angle. Rectangular and circular
+patterns also appear as children beneath their sketch in the browser and left
+feature history. Expand the sketch to find them; double-click a
+pattern to open its saved editor, including from a finished sketch. Surviving copies keep
+their IDs. Patterns support undo/redo and survive saving and reopening.
+
+The same operations are available through `sketch.mirror`,
+`sketch.pattern.rectangular` and `sketch.pattern.circular`. For example:
+
+```json
+{
+  "command": "sketch.pattern.rectangular",
+  "params": {
+    "entities": ["l1", "l2", "l3"],
+    "direction": "guide1",
+    "direction2": "guide2",
+    "count": 3,
+    "spacing": 20,
+    "count2": 2,
+    "spacing2": 10,
+    "alignment": "center",
+    "alignment2": "center",
+    "reversed": false,
+    "reversed2": true
+  }
+}
+```
+
+`direction` and `direction2` reference sketch line IDs. `dir` and `dir2`
+instead accept fixed `[x,y]` vectors. Distances are millimetres; the circular
+command's `angle` parameter is in degrees. The combined quantity is capped at 500.
+Deleting a direction line breaks its rectangular pattern association and leaves
+the remaining geometry in place; undo restores the association.
+
+Circular patterns accept the same `alignment` and `reversed` parameters, for example
+`{"entities":["hole"],"center":[0,0],"count":6,"angle":90,"alignment":"center","reversed":false}`.