Standardize parameter labels to sentence case

Applied sentence case formatting to all parameter label fields while
preserving proper names (Bank of England, Child Benefit, etc.) and
acronyms (HMRC, VAT, NHS, etc.).

Fixes #1461

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: 2 people

changelog_entry.yaml

@@ -1,5 +1,4 @@
 - bump: patch
   changes:
-    fixed:
-      - CI now runs on dependency updates (pyproject.toml, uv.lock changes)
-      - Fixed Scottish Child Payment test format to use array notation for person-level output
+    changed:
+      - Standardized all parameter labels to use sentence case, while preserving proper names (e.g., "Bank of England", "Child Benefit") and acronyms (e.g., "HMRC", "VAT", "NHS")

policyengine_uk/parameters/gov/contrib/conservatives/cb_hitc_household.yaml

@@ -3,4 +3,4 @@ values:
   2000-01-01: false
 metadata:
   unit: bool
-  label: household-based High Income Tax Charge
+  label: Household-based high Income Tax charge

policyengine_uk/parameters/gov/contrib/conservatives/pensioner_personal_allowance.yaml

@@ -7,4 +7,4 @@ values:
   2025-04-06: 12_570
 metadata:
   unit: currency-GBP
-  label: personal allowance for pensioners
+  label: Personal allowance for pensioners

policyengine_uk/parameters/gov/contrib/labour/private_school_vat.yaml

@@ -3,4 +3,4 @@ values:
   2000-01-01: 0
 metadata:
   unit: /1
-  label: private school VAT rate
+  label: Private school VAT rate

policyengine_uk/parameters/gov/contrib/policyengine/budget/consumer_incident_tax_change.yaml

@@ -2,4 +2,4 @@ description: Tax increase incident on consumers.
 values:
   2000-01-01: 0
 metadata:
-  label: tax on consumers (£bn)
+  label: Tax on consumers (£bn)

policyengine_uk/parameters/gov/contrib/policyengine/budget/corporate_incident_tax_change.yaml

@@ -2,4 +2,4 @@ description: Tax increase incident on owners of capital.
 values:
   2000-01-01: 0
 metadata:
-  label: tax on capital (£bn)
+  label: Tax on capital (£bn)

policyengine_uk/parameters/gov/contrib/policyengine/budget/education.yaml

@@ -2,4 +2,4 @@ description: Increase in education, distributed by income decile as estimated by
 values:
   2000-01-01: 0
 metadata:
-  label: education spending change (£bn)
+  label: Education spending change (£bn)

policyengine_uk/parameters/gov/contrib/policyengine/budget/high_income_incident_tax_change.yaml

@@ -2,4 +2,4 @@ description: Tax rise for high income earners (functioning proportional to incom
 values:
   2000-01-01: 0
 metadata:
-  label: high income incident tax change (£bn)
+  label: High income incident tax change (£bn)

policyengine_uk/parameters/gov/contrib/policyengine/budget/other_public_spending.yaml

@@ -2,4 +2,4 @@ description: Increase in non-NHS, non-education public spending, distributed by
 values:
   2000-01-01: 0
 metadata:
-  label: general public spending change (£bn)
+  label: General public spending change (£bn)

policyengine_uk/parameters/gov/contrib/policyengine/disable_simulated_benefits.yaml

@@ -2,4 +2,4 @@ description: Disable simulated benefits.
 values:
   2000-01-01: false
 metadata:
-  label: disable simulated benefits
+  label: Disable simulated benefits