feat: add semantic gravity examples script and Axis 1 shift analysis

- Add script to find motions closest to semantic gravity per axis/window
- Document Axis 1 semantic shift: from administrative law (2016)
  to migration/asylum policy (2026)
- Shows that 'coalition' votes on different topics over time

docs/research/2026-04-05-axis1-semantic-shift-examples.md

@@ -0,0 +1,68 @@
+# Semantic Content Shift: Axis 1 Over Time
+
+## What Changed: "Coalition vs Opposition" Axis Content
+
+| Year | Positive Pole (Coalition) | Negative Pole (Opposition) | Key Theme |
+|------|-------------------------|---------------------------|-----------|
+| **2016** | Tax law changes, international treaties | — | Administrative law |
+| **2018** | Budget modifications, infrastructure, social affairs | — | Government spending |
+| **2019** | Working conditions, monitoring issues | — | Administrative oversight |
+| **2022** | Local government info, digital accounts | Digital governance, privacy | Digital transformation |
+| **2023** | Welfare policy, parental support | Social services | Social policy |
+| **2024** | Nuclear weapons, housing, Israel boycott | — | Foreign policy / Justice |
+| **2025** | EU sanctions on Israel, asylum policies | — | Migration / Foreign affairs |
+| **2026** | **Asylum stops**, Syrian permit revocations, Ukraine returns | IND backlog | **Migration dominates** |
+
+## Key Observations
+
+### 1. The "Coalition" Side Evolved Significantly
+
+| Period | Coalition Motions Focused On |
+|--------|---------------------------|
+| 2016-2019 | Administrative law, tax, budgets, infrastructure |
+| 2022-2023 | Digital governance, welfare, social services |
+| 2024-2025 | Foreign policy (Israel sanctions), migration |
+| **2026** | **Asylum restriction**, Syria, Ukraine returns |
+
+### 2. Axis 1 Became Migration-Centric by 2026
+
+In 2026, the **extreme positive motions** are ALL about asylum/migration:
+- "Motie van het lid Vondeling over een totale asielstop" (total asylum stop)
+- "Motie van het lid Vondeling over alle tijdelijke asielvergunningen van Syriërs intrekken" (revoke Syrian permits)
+- "Motie van het lid Vondeling over een actief terugkeerbeleid voor alle Oekraïners" (active return policy for Ukrainians)
+
+This suggests the coalition/opposition dynamic in 2026 is increasingly defined by **migration policy** rather than the traditional left-right economic divide.
+
+### 3. The "Typical" Motion Changed
+
+Semantic gravity represents the "typical" motion on the axis. Its content shifted:
+
+| Year | Typical Motion Theme |
+|------|---------------------|
+| 2016 | Tax law, health law, financial administration |
+| 2019 | Bureaucracy reduction, Kamer control, administrative burden |
+| 2023 | Student finance, volunteer work, housing |
+| 2024 | Fossil fuel phase-out, whistleblower protection, youth care |
+| 2026 | Asylum, IND backlog, Ukraine, social grievances |
+
+## Implications
+
+1. **Axis label is temporally bounded**: "Rechts kabinetsbeleid versus links oppositiebeleid" works for 2016-2026 as a whole, but in 2026 it's increasingly about migration policy.
+
+2. **Party voting structure is stable** (0.83 stability), but **what parties vote on** has shifted from economics to migration.
+
+3. **Axis 6 (Migration/Culture)** low stability (0.35) may now be overlapping with Axis 1 — migration has become a coalition-defining issue.
+
+## Example: Concrete Before/After
+
+**2016 - "Coalition" side:**
+> "Wijziging van enkele belastingwetten en enige andere wetten (Fiscale vereenvoudigingswet 2017)"
+
+**2026 - "Coalition" side:**
+> "Motie van het lid Vondeling over een totale asielstop"
+
+Same axis (coalition votes FOR), but semantically completely different topics.
+
+---
+
+*Generated by `scripts/semantic_gravity_examples.py`*