feat(meos): W6 codegen — tgeo restriction at/minus geom (2 ops + 1 template + 1 systest) (stacks on #28)

[estebanzimanyi]

Summary

First restriction-shape operators. MEOS signature is
Temporal* fn(const Temporal*, const GSERIALIZED*) — returns the
clipped Temporal* (non-null if input survives the restriction,
null if clipped to empty).

For per-event single-instant inputs (the codegens current shape), the
restriction collapses to a filter predicate: 1 if the point survives,
0 if clipped. This mirrors marianas TemporalAtStBox int-collapse
pattern exactly — see TemporalAtStBoxPhysicalFunction.cpp:90 for the
hand-written precedent (clipped.get() != nullptr ? 1 : 0).

MEOS function	NebulaStream operator	survives if …
tgeo_at_geom	TemporalAtGeometry	point inside the static geom
tgeo_minus_geom	TemporalMinusGeometry	point outside the static geom

Honest semantic note

Per-event single-instant TEMPORAL_AT_GEOMETRY is semantically
equivalent to TEMPORAL_ECONTAINS_GEOMETRY (PR #23), and
TEMPORAL_MINUS_GEOMETRY ≡ TEMPORAL_EDISJOINT_GEOMETRY. The
restriction ops only add genuinely new SQL surface when the input
tgeompoint is a sequence of multiple instants (W7-territory —
windowed aggregations), where clipping produces a different sequence
than the original. Shipped now because:

1. They round out the SQL surface PostGIS / MobilityDB users expect
   (the AT/MINUS idiom is standard there).
2. They exercise the codegens first restriction-shape template,
   which W7 sequence-aggregated restriction will inherit.
3. The collapse-to-int return matches marianas TemporalAtStBox
   so downstream consumers see a consistent shape across at/minus ops.

Generator additions

• PHYSICAL_CPP_TEMPLATE_TEMPORAL_POINT_RESTRICTION
  — calls Temporal* {meos_call}(...), checks non-null, free()s,
  returns int. Flag: build_temporal_point_restriction.
• dispatch_case_for() reuses the existing
  DISPATCH_CASE_ONE_TEMPORAL_POINT template — same 4-arg parser
  shape (lon, lat, ts, geom), only the physical-cpp body shape
  differs (Temporal* return vs int return).

Per-shape systest

Tests/Functions/at_geometry.test exercises TEMPORAL_AT_GEOMETRY:
one point inside a polygon (expect 1), one outside (expect 0).

Local verification

nes-development:mobilitynebula-v2:

cmake --build build-w1 --target nes-physical-operators -j 4
  → [49/49] Linking libnes-physical-operators.a
cmake --build build-w1 --target nes-logical-operators  -j 4
  → [63/63] Linking libnes-logical-operators.a
cmake --build build-w1 --target nes-sql-parser         -j 4
  → [11/11] Linking libnes-sql-parser.a

All three targets link clean on the first attempt.

Stack

#21 tools(codegen): generator + design
  └── #22 fix(meos): proto extra_fields + Werror unused-param
        └── #23 feat(meos): W1 — 5 spatial-rel ops (tgeo × geom)
              └── #24 feat(meos): W2 — close _tgeo_geo row
                    └── #25 feat(meos): W3 — close _tgeo_tgeo row
                          └── #26 feat(meos): W4 — distance family
                                └── #27 feat(codegen): W4.5 parser glue
                                      └── #28 feat(meos): W5a — tnumber NAD
                                            └── THIS PR — W6: restriction at/minus geom