Relax numpy/pandas/scipy/sympy/networkx pins to support modern stack

Replace the `~=` upper caps with lower-bound floors. The caps blocked
numpy 2 / pandas 2+ / networkx 3 and made Python 3.14 impossible
(pandas 1.x has no cp314 wheels), blocking the downstream RealRate-Private
uv / Python 3.14 migration.

Verified equivalent across the stack jump:
- causing unit suite: 24/24 pass on Python 3.14 + numpy 2 / pandas 3 / networkx 3
- make verify-output: all 5 example graphs.json byte-identical to baseline
- RealRate de_life_insurance A/B: 8/8 years identical within 1e-10

Bump version 2.4.6 -> 2.5.0.

Refs: realrate/RealRate-Private#2098

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: bbkrr

setup.py

@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name="causing",
-    version="2.4.6",
+    version="2.5.0",
     author="Dr. Holger Bartel",
     author_email="holger.bartel@realrate.ai",
     description="Causing: CAUSal INterpretation using Graphs",
@@ -19,11 +19,15 @@
         "Operating System :: OS Independent",
     ],
     install_requires=[
-        "numpy~=1.23",
-        "pandas~=1.3",
-        "scipy~=1.9",
-        "sympy~=1.5",
-        "networkx~=2.7",
+        # Lower-bound floors only: the previous `~=` upper caps blocked numpy 2 /
+        # pandas 2+ / networkx 3 and made Python 3.14 impossible (no pandas 1.x cp314
+        # wheels). Verified numerically equivalent across the stack jump — see
+        # https://github.com/realrate/RealRate-Private/issues/2098
+        "numpy>=1.23",
+        "pandas>=1.3",
+        "scipy>=1.9",
+        "sympy>=1.5",
+        "networkx>=2.7",
         "pre-commit",  # TODO: move to dev-requirements
     ],
     python_requires=">=3.9",