feat: make supported chains list dynamic via getSupportedChains API

docs/base-account/overview/what-is-base-account.mdx

@@ -12,16 +12,13 @@ A Base Account is a Smart-Wallet–backed account that gives every user:
 * **Universal sign-on** – one passkey works across every Base-enabled app.
 * **One-tap payments** – low-friction USDC payments built into the account layer.
 * **Private profile vault** – opt-in sharing of email, phone, shipping address, and more.
-* **Multi-chain support** – one address that works across nine EVM networks (and counting).
+* **Multi-chain support** – one address that works across many EVM networks.
 
-> Under the hood, each Base Account is an ERC-4337 Smart Wallet that can be deployed on any EVM-compatible chain; nine EVM mainnet chains are enabled out of the box, including Base Mainnet.
+> Under the hood, each Base Account is an ERC-4337 Smart Wallet that can be deployed on any EVM-compatible chain; many EVM mainnet chains are enabled out of the box, including Base Mainnet.
 
-<Note>
-**Supported networks**
+import SupportedChains from "/snippets/supported-chains.mdx";
 
-- **Mainnet:** Base • Arbitrum • Optimism • Zora • Polygon • BNB • Avalanche • Lordchain • Ethereum Mainnet (not recommended due to costs)
-- **Testnet:** Sepolia • Base Sepolia
-</Note>
+<SupportedChains />
 
 ## Why should developers care?
 

docs/snippets/supported-chains.mdx

@@ -0,0 +1,12 @@
+{/* Auto-generated by scripts/update-supported-chains.sh — do not edit manually */}
+
+<Note>
+**Supported networks**
+
+**Full support**
+- **Mainnet:** Base • Arbitrum • Optimism • Zora • Polygon • BNB Chain • Avalanche • Ethereum
+- **Testnet:** Base Sepolia • Sepolia
+
+{/* DYNAMIC_CHAINS_START */}
+{/* DYNAMIC_CHAINS_END */}
+</Note>

scripts/update-supported-chains.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+# Fetches the SCW getSupportedChains API and regenerates the
+# docs/snippets/supported-chains.mdx file, inserting any chains
+# tagged "simple-chain" into the dynamic section.
+#
+# Usage:
+#   bash scripts/update-supported-chains.sh
+#
+# The snippet has two parts:
+#   1. Hardcoded core chains (manually maintained above the markers)
+#   2. Dynamic "basic chains" pulled from the API (between the markers)
+#
+# Only chains with the "simple-chain" tag are inserted dynamically.
+# If none are found, the dynamic section is left empty.
+
+set -euo pipefail
+
+API_URL="${API_URL:-https://api.wallet.coinbase.com/rpc/v3/scw/getSupportedChains}"
+SNIPPET="docs/snippets/supported-chains.mdx"
+
+# Resolve paths relative to repo root
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+SNIPPET_PATH="$REPO_ROOT/$SNIPPET"
+
+if [ ! -f "$SNIPPET_PATH" ]; then
+  echo "Error: $SNIPPET not found at $SNIPPET_PATH" >&2
+  exit 1
+fi
+
+# Fetch the API
+RESPONSE=$(curl -sf "$API_URL") || {
+  echo "Error: failed to fetch $API_URL" >&2
+  exit 1
+}
+
+# Extract simple-chain entries grouped by mainnet/testnet
+DYNAMIC_BLOCK=$(echo "$RESPONSE" | python3 -c "
+import sys, json
+
+data = json.load(sys.stdin)
+chains = data.get('chains', [])
+
+simple = [c for c in chains if 'simple-chain' in c.get('tags', [])]
+
+if not simple:
+    sys.exit(0)  # nothing to output
+
+mainnets = sorted([c['name'] for c in simple if 'testnet' not in c['networkId']])
+testnets = sorted([c['name'] for c in simple if 'testnet' in c['networkId']])
+
+all_simple = sorted(mainnets + testnets)
+
+lines = []
+lines.append('**Basic support:** ' + ' • '.join(all_simple))
+lines.append('')
+lines.append('Basic support only includes transfers through the [Base Account Web](https://account.base.app) surface for select tokens.')
+
+print('\n'.join(lines))
+")
+
+# Replace content between the markers in the snippet
+python3 -c "
+import sys
+
+snippet_path = sys.argv[1]
+dynamic_block = sys.argv[2]
+
+with open(snippet_path, 'r') as f:
+    content = f.read()
+
+start_marker = '{/* DYNAMIC_CHAINS_START */}'
+end_marker = '{/* DYNAMIC_CHAINS_END */}'
+
+start_idx = content.find(start_marker)
+end_idx = content.find(end_marker)
+
+if start_idx == -1 or end_idx == -1:
+    print('Error: markers not found in snippet', file=sys.stderr)
+    sys.exit(1)
+
+# Build the replacement: markers + dynamic content between them
+if dynamic_block.strip():
+    replacement = start_marker + '\n' + dynamic_block + '\n' + end_marker
+else:
+    replacement = start_marker + '\n' + end_marker
+
+new_content = content[:start_idx] + replacement + content[end_idx + len(end_marker):]
+
+with open(snippet_path, 'w') as f:
+    f.write(new_content)
+" "$SNIPPET_PATH" "$DYNAMIC_BLOCK"
+
+echo "Updated $SNIPPET"