docs: restructure base-chain IA and recover consolidated content (#1666)

* docs: restructure base-chain IA and recover consolidated content

Reorganize the Base Chain docs information architecture and audit the
restructure for content loss against the previously published pages.

Navigation:
- Replace "Quickstart" with a single "Introduction" (overview) entry
- Add "Core Concepts" (transaction ordering, finality, throughput and
  limits, network fees, bridging and withdrawals)
- Add "Network Reference" (connecting, node providers, contracts,
  bridges, faucets, Flashblocks Reference, troubleshooting, changelog)
- Move deploy-on-base into the Apps quickstart
- Add redirects for every removed/moved path

Content consolidation and recovery:
- Restore the Configuration Changelog (full Mainnet + Sepolia history),
  re-add it to nav, and restore the network-fees cross-link
- Rename the Flashblocks FAQ to "Flashblocks Reference" and add key
  concepts, architecture (sequencer + Flashblocks components), and
  further reading (deep dive + Flashbots credit)
- Add a focused Flashblocks section to the build-an-app guide
- Add Flashblock performance metrics to throughput-and-limits

Accuracy:
- Update block capacity to current values: full block ~400M gas
  (was 140M) and first Flashblock ~40M (was 14M)
- Reframe Flashblock-1 gas guidance: the per-transaction gas maximum
  (~16.7M) is below Flashblock 1's ~40M capacity, so any valid
  transaction fits in the first Flashblock

Regenerate llms.txt and llms-full.txt.

Generated with Claude Code

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

* Update snapshot links, flashblock api method order, and removed upcoming section

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: ericbrown99

docs/AGENTS.md

@@ -11,7 +11,7 @@ description: Look up Base documentation with a compact directory-grouped index b
 - [Agents](./agents/llms.txt) — Give your AI assistant a wallet. Base MCP connects any AI to your Base Account. Check balances, send funds, swap tokens, sign messages, and pay with x402.
 - [Apps](./apps/llms.txt) — A step-by-step guide to building a Next.js tally app on Base using wagmi and viem, with wallet connection, contract reads and writes, and batch transaction support.
 - [Base Account](./base-account/llms.txt)
-- [Base Chain](./base-chain/llms.txt) — Bridge tokens and messages between Base and Solana Mainnet
+- [Base Chain](./base-chain/llms.txt) — Start here for Base Chain docs, including concepts, network reference, node operation, APIs, and protocol specifications.
 - [Get Started](./get-started/llms.txt)
 - [Ledgers](./ledgers/llms.txt) — An introduction to Base Ledgers, the enterprise way to run confidential payments that settle on Base.
 - [Static](./static/llms.txt)
@@ -50,7 +50,7 @@ npx skills add base/base-skills
 |apps/builder-codes:agent-developers,app-developers,builder-codes,wallet-developers
 |apps/growth:rewards
 |apps/guides:accept-b20-payments,migrate-to-standard-web-app
-|apps/quickstart:build-app
+|apps/quickstart:build-app,deploy-on-base
 |apps/resources:design-resources,templates
 |apps/technical-guides:base-notifications
 |base-account/basenames:basename-transfer,basenames-faq
@@ -74,14 +74,15 @@ npx skills add base/base-skills
 |base-account/reference/prolink-utilities:createProlinkUrl,decodeProlink,encodeProlink
 |base-account/reference/spend-permission-utilities:fetchPermission,fetchPermissions,getPermissionStatus,prepareRevokeCallData,prepareSpendCallData,requestRevoke,requestSpendPermission
 |base-account/reference/ui-elements:base-pay-button,brand-guidelines,sign-in-with-base-button
+|base-chain:overview
 |base-chain/api-reference:rpc-overview
 |base-chain/api-reference/debug-api:debug_traceBlockByHash,debug_traceBlockByNumber,debug_traceTransaction
 |base-chain/api-reference/ethereum-json-rpc-api:eth_blockNumber,eth_call,eth_chainId,eth_estimateGas,eth_feeHistory,eth_gasPrice,eth_getBalance,eth_getBlockByHash,eth_getBlockByNumber,eth_getBlockReceipts,eth_getBlockTransactionCountByHash,eth_getBlockTransactionCountByNumber,eth_getCode,eth_getLogs,eth_getStorageAt,eth_getTransactionByBlockHashAndIndex,eth_getTransactionByBlockNumberAndIndex,eth_getTransactionByHash,eth_getTransactionCount,eth_getTransactionReceipt,eth_maxPriorityFeePerGas,eth_sendRawTransaction,eth_subscribe,eth_syncing,eth_unsubscribe,net_version,web3_clientVersion
 |base-chain/api-reference/flashblocks-api:base_transactionStatus,eth_simulateV1,flashblocks-api-overview,newFlashblockTransactions,newFlashblocks,pendingLogs
-|base-chain/flashblocks:app-integration,architecture,faq,overview
-|base-chain/network-information:base-contracts,block-building,bridges,configuration-changelog,diffs-ethereum-base,network-faucets,network-fees,transaction-finality,troubleshooting-transactions
+|base-chain/flashblocks:faq
+|base-chain/network-information:base-contracts,base-solana-bridge,bridging-and-withdrawals,ecosystem-bridges,network-faucets,network-fees,throughput-and-limits,transaction-finality,transaction-ordering,troubleshooting-transactions
 |base-chain/node-operators:node-providers,performance-tuning,run-a-base-node,snapshots,troubleshooting
-|base-chain/quickstart:base-solana-bridge,connecting-to-base,deploy-on-base,why-base
+|base-chain/quickstart:connecting-to-base
 |base-chain/security:avoid-malicious-flags,bug-bounty,report-vulnerability,security-council
 |base-chain/specs:overview
 |base-chain/specs/protocol:batcher,overview

docs/apps/quickstart/build-app.mdx

@@ -537,6 +537,29 @@ Base is a fast, low-cost Ethereum L2 built to bring the next billion users oncha
   </Step>
 </Steps>
 
+## Speed up confirmations with Flashblocks
+
+Base builds [Flashblocks](/base-chain/network-information/transaction-ordering#flashblocks) — 200ms incremental blocks that let your app reflect transaction confirmations roughly 10x faster than the standard 2-second block time. Flashblocks are always live; you opt in by pointing Wagmi at a Flashblocks-aware chain, with no other code changes. `useWaitForTransactionReceipt` then resolves against pre-confirmed state.
+
+Swap the standard chain for its `Preconf` variant in `config/wagmi.ts`:
+
+```typescript config/wagmi.ts highlight={2,5,8}
+import { http, createConfig } from 'wagmi'
+import { baseSepoliaPreconf } from 'wagmi/chains'
+
+export const config = createConfig({
+  chains: [baseSepoliaPreconf],
+  // ...connectors and storage unchanged
+  transports: {
+    [baseSepoliaPreconf.id]: http(),
+  },
+})
+```
+
+<Note>
+For production, the public endpoints are rate-limited — connect through a Flashblocks-enabled [node provider](/base-chain/node-operators/node-providers). For the underlying RPC behavior (the `pending` block tag and supported methods), see the [RPC Overview](/base-chain/api-reference/rpc-overview#flashblocks) and the [Flashblocks Reference](/base-chain/flashblocks/faq).
+</Note>
+
 ## Next steps
 
 - **Go to mainnet** — add `base` to your `chains` array and transports in `config/wagmi.ts`, redeploy your contract to Base mainnet, and update `COUNTER_ADDRESS`.

…base-chain/quickstart/deploy-on-base.mdx docs/apps/quickstart/deploy-on-base.mdxdocs/base-chain/quickstart/deploy-on-base.mdx renamed to docs/apps/quickstart/deploy-on-base.mdx docs/base-chain/quickstart/deploy-on-base.mdx renamed to docs/apps/quickstart/deploy-on-base.mdx

@@ -1,5 +1,6 @@
 ---
 title: 'Deploy on Base'
+description: Deploy a smart contract to Base Sepolia with Foundry.
 ---
 
 Welcome to the Base deployment quickstart guide! This comprehensive walkthrough will help you set up your environment and deploy smart contracts on Base. Whether you're a seasoned developer or just starting out, this guide has got you covered.
@@ -122,7 +123,7 @@ Note the format of the contract being deployed is `<contract-path>:<contract-nam
 
 3. After successful deployment, you'll see output including:
 
-```
+```text
 Deployer: 0x...
 Deployed to: 0x...  <-- YOUR CONTRACT ADDRESS
 Transaction hash: 0x...

docs/base-chain/api-reference/ethereum-json-rpc-api/eth_call.mdx

@@ -11,7 +11,7 @@ Executes a message call immediately without broadcasting a transaction to the ne
 </Tip>
 
 <Note>
-**`eth_call "pending"` block context on Flashblocks nodes:** Block-context properties (`block.number`, `block.timestamp`, `block.basefee`) may reflect a block several behind tip due to how nodes cache historical Flashblocks. See the [FAQ](/base-chain/flashblocks/faq#why-does-eth_call-pending-report-a-block-context-several-blocks-behind-tip) for details.
+**`eth_call "pending"` block context on Flashblocks nodes:** Block-context properties (`block.number`, `block.timestamp`, `block.basefee`) may reflect a block several behind tip due to how nodes cache historical Flashblocks. See the [FAQ](/base-chain/flashblocks/faq#why-does-eth_call-pending-report-a-block-number-several-blocks-behind-tip) for details.
 </Note>
 
 ## Parameters

docs/base-chain/api-reference/flashblocks-api/flashblocks-api-overview.mdx

@@ -50,7 +50,7 @@ Unique identifier for the block being built. Remains consistent across all Flash
 </ParamField>
 
 <ParamField path="index" type="number">
-Flashblock index within the current block. Starts at 0 (system transactions only). User transactions begin at index 1. Typically reaches 9–10 per block, but [may exceed 10](/base-chain/flashblocks/faq#why-can-the-flashblock-index-exceed-10) during sequencer timing drift.
+Flashblock index within the current block. Starts at 0 (system transactions only). User transactions begin at index 1. Typically reaches 9–10 per block, but [may exceed 10](/base-chain/flashblocks/faq#can-the-flashblock-index-exceed-10-is-that-a-bug) during sequencer timing drift.
 </ParamField>
 
 <ParamField path="base" type="Base Object">