docs: Add contact resolution, Makefile, contributing to all docs

- README: contact name resolution section, Makefile mention
- CHANGELOG: contact resolution, Makefile, contributing, error messages
- CLAUDE.md: ResolveAddress in architecture

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: GrapeInTheTree

CHANGELOG.md

@@ -33,6 +33,13 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 - **`CallContract()`** RPC function — `eth_call` wrapper
 - **`DecodeRawOutputs()`** — returns raw Go types (not strings) for programmatic use
 - **22 unit tests** for ABI helper functions (ParseCallSignature, ConvertArg, FormatValue, BuildCalldata)
+- **Contact name resolution** — all address commands accept names from `contacts.json`
+  - Case-insensitive partial match: `butler address danial` → resolves to 0xef33...
+  - Actionable error messages: "address or contact not found" with hint
+- **Makefile** — `make build`, `make test`, `make vet`, `make clean`, `make run`
+- **CONTRIBUTING.md** — development setup, project structure, PR process
+- **GitHub templates** — bug report, feature request, PR template
+- **Improved error messages** — config loading errors include actionable hints with docs link
 
 ## [0.2.0] - 2026-03-27
 

CLAUDE.md

@@ -113,6 +113,7 @@ internal/
                                     ResolveConfigDir() cascade: --config > env > ~/.butler/ > CWD
                                     configPath() joins configDir + filename (empty configDir = relative)
                                     GetPrivateKey() reads key from env only at signing time
+                                    ResolveAddress() resolves contact names or validates 0x addresses
                                     Wallets hardcoded: Main Wallet + Test Wallet
 
     ethereum/

README.md

@@ -107,6 +107,16 @@ Global flags:
   -h, --help         Help for any command
 ```
 
+### Contact Name Resolution
+
+All address commands support contact names from `contacts.json`:
+
+```bash
+butler address danial           # resolves to 0xef33...d93c
+butler staking kayen            # resolves to 0x86d3...8897
+butler address 0xC3B2...D2c49   # direct address still works
+```
+
 ### butler address
 
 Comprehensive address overview — 5 concurrent fetches (3 RPC + 2 Explorer) for fast response.