improve: update skill categories and titles

[marc0olo]

Changes

Category restructure

• Architecture → Core — better reflects the mix of language (Motoko), pattern (Multi-Canister), and runtime concern (Stable Memory)
• Tokens + Wallet → DeFi — removes two single-skill categories; DeFi now groups all financial primitives: ckBTC, ICRC Token Ledgers, Wallet Integration

Title updates

Skill	Before	After
ckbtc	ckBTC Integration	ckBTC (chain-key Bitcoin)
icrc-ledger	ICRC Ledger Standard	ICRC Token Ledgers
evm-rpc	EVM RPC Integration	EVM RPC
internet-identity	Internet Identity Auth	Internet Identity
asset-canister	Asset Canister & Frontend	Asset Canister

Supporting changes

• Icons.tsx: renamed "Architecture" case to "Core", removed "Tokens" and "Wallet" cases (DeFi icon covers those skills now)
• scripts/check-project.js: updated KNOWN_CATEGORIES
• skills/skill.schema.json: updated category description
• CLAUDE.md + CONTRIBUTING.md: updated known categories lists
• skills/asset-canister/SKILL.md: updated H1 body heading to match new title

Resulting categories

Auth · Core · DeFi · Frontend · Governance · Infrastructure · Integration · Security

[github-actions]

Skill Validation Report

Project Checks

WARNINGS (3):
  ⚠ ckbtc/SKILL.md: missing evaluations/ckbtc.json — see CONTRIBUTING.md for evaluation guidance
  ⚠ multi-canister/SKILL.md: missing evaluations/multi-canister.json — see CONTRIBUTING.md for evaluation guidance
  ⚠ stable-memory/SKILL.md: missing evaluations/stable-memory.json — see CONTRIBUTING.md for evaluation guidance

✓ Project checks passed for 9 skills (3 warnings)