Static Types pcpoint and pcpatch

Static Types `pcpoint` and `pcpatch`
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Static Types `pcpoint` and `pcpatch`

The static types come from pgPointCloud. MobilityDB exposes the schema-aware coordinate accessors needed to project pgPointCloud values into the rest of the temporal-types ecosystem.

Ergonomic constructors

pgPointCloud's pcpoint_in only accepts hex-WKB, so the canonical builder is PC_MakePoint(pcid, ARRAY[…]::float[]). MobilityDB ships two thin SQL overloads on top of it for shorter test literals and ad-hoc queries; the underlying schema-dimension validation still happens inside PC_MakePoint.

Build a 2D or 3D pcpoint directly from x/y(/z) coordinates
pcpoint(pcid integer, x float, y float) → pcpoint
pcpoint(pcid integer, x float, y float, z float) → pcpoint
```
SELECT pcpoint(1, 10.0, 20.0, 30.0);
-- equivalent to PC_MakePoint(1, ARRAY[10.0, 20.0, 30.0]::float[])
```

Build a pcpatch from a variadic list of pcpoints sharing the same pcid

pcpatch(pcid integer, VARIADIC points pcpoint[]) → pcpatch

SELECT pcpatch(1, pcpoint(1, 1.0, 1.0, 1.0), pcpoint(1, 2.0, 2.0, 2.0));
-- equivalent to PC_Patch(ARRAY[PC_MakePoint(1, ARRAY[1.0, 1.0, 1.0]::float[]),
--                              PC_MakePoint(1, ARRAY[2.0, 2.0, 2.0]::float[])])

Accessors

Return the schema id of a pcpoint or pcpatch
pcid(pcpoint) → integer
pcid(pcpatch) → integer
```
SELECT pcid(PC_MakePoint(1, ARRAY[10.0, 20.0, 30.0]));
-- 1
```
Return a coordinate of a pcpoint, NULL if the dimension is absent from the schema
getX(pcpoint) → float
getY(pcpoint) → float
getZ(pcpoint) → float
```
WITH pt AS (SELECT PC_MakePoint(1, ARRAY[10.0, 20.0, 30.0]) p)
  SELECT getX(p), getY(p), getZ(p) FROM pt;
-- 10 | 20 | 30
```
Return any named dimension of a pcpoint, NULL if the name is unknown for the schema
getDim(pcpoint,text) → float
```
SELECT getDim(PC_MakePoint(1, ARRAY[10.0, 20.0, 30.0]), 'X');
-- 10
```
Return the spatial reference identifier (inherited from the schema)
SRID(pcpoint) → integer
SRID(pcpatch) → integer
```
SELECT SRID(PC_MakePoint(1, ARRAY[10.0, 20.0, 30.0]));
-- 0
```