Add Solidity linting with solhint, Foundry formatter, and pre-commit hooks

- Added .solhint.json with recommended rules + custom config
  - 160 char line length (warn)
  - Double quotes enforcement (error)
  - Explicit visibility required (error)
  - Console statements allowed (scripts/tests need them)
  - Gas optimization warnings enabled
  - Ignores test/helpers/, lib/, out/, cache/, broadcast/

- Added foundry.toml [fmt] section
  - 160 char line length
  - 4-space tabs
  - Double quotes
  - Thousands separators for numbers
  - Sort imports enabled

- Added .lintstagedrc.json for pre-commit auto-fix
  - Runs solhint --fix on .sol files
  - Runs forge fmt on .sol files

- Added husky pre-commit hook via lint-staged

- lint:sol - run solhint
- lint:sol:fix - auto-fix solhint issues
- format:sol - format with forge fmt
- format:sol:check - check formatting
- lint / lint:fix - combined commands

- Added explicit visibility modifiers (internal) to constants in scripts and tests
- Fixed quote style in DeployLocal.sol
- All Solidity files formatted with forge fmt

- ✅ forge fmt --check passes
- ✅ No solhint errors (warnings only)
- ✅ forge build succeeds
- ✅ forge test passes (107/107)

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

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

onchain/script/DeployBaseSepolia.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 pragma solidity ^0.8.19;
 
-import {DeployBase} from "./DeployBase.sol";
+import { DeployBase } from "./DeployBase.sol";
 
 /**
  * @title DeployBaseSepolia
@@ -19,4 +19,4 @@ contract DeployBaseSepolia is DeployBase {
         // optimizer = 0xFCFa3b066981027516121bd27a9B1cBb9C00c5Fd;
         optimizer = address(0); // Deploy new optimizer
     }
-}
+}