feat(Badge): add label prop for API consistency

[cixzhang]

Problem

Vibe testing: LLMs write <XDSBadge label="Active" /> 100% of the time without docs, because Button, Token, and ListItem all use label. With docs they use children correctly — but the API shouldn't fight developer expectations.

Condition	children (current)	label (hallucinated)
With docs	8/8 ✅	0/8
Without docs	0/8	8/8 ❌

Fix

Add label prop to XDSBadge. Both work:

<XDSBadge variant="success" label="Active" />    // new — matches Button/Token pattern
<XDSBadge variant="success">Active</XDSBadge>     // still works — for advanced cases

children overrides label when both are provided.

Changes

• XDSBadge: new label prop, children deprecated for simple text
• All usages updated across example apps, storybook, doc files
• Codemod: migrate-badge-children-to-label in v0.0.5 transforms
• 7/7 Badge tests pass

Closes #706

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[github-actions]

PR Analysis Report

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Modified Components

Badge · View in Storybook

Metric	Before	After	Delta
Bundle Size (ESM)	N/A	203B	N/A
Lines of Code	N/A	132	-
Complexity	N/A	Low (3)	-

Button · View in Storybook

Metric	Before	After	Delta
Bundle Size (ESM)	N/A	333B	N/A
Lines of Code	N/A	292	-
Complexity	N/A	High (22)	-

SideNav · View in Storybook

Metric	Before	After	Delta
Bundle Size (ESM)	N/A	1.1KB	N/A
Lines of Code	N/A	1338	-
Complexity	N/A	Very High (133)	-

Table · View in Storybook

Metric	Before	After	Delta
Bundle Size (ESM)	N/A	863B	N/A
Lines of Code	N/A	847	-
Complexity	N/A	Very High (54)	-

Bundle Size Summary

Package	Size (ESM)	Size (CJS)	Gzipped
@xds/core	10.7KB	17.0KB	2.6KB

Accessibility Audit

Status: 2 accessibility violation(s) found — 2 serious.

XDSSideNav - 1 issue(s)

• 🟠 serious: Ensure links have discernible text
  • Rule: link-name · Affects 1/8 stories · Learn more
  • WCAG: 2.4.4, 4.1.2 (Level A)

Selection - 1 issue(s)

• 🟠 serious: Ensure ARIA attributes are used as described in the specification of the element's role
  • Rule: aria-conditional-attr · Affects 1/7 stories · Learn more
  • WCAG: 4.1.2 (Level A)

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