chore: update branch references for main/legacy rename (ENG-2105)

Update CI triggers, CLAUDE.md, CONTRIBUTING.md, and README.md to
reflect the branch rename: develop → main, main → legacy.

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

Author: prestwich

.github/workflows/rust.yml

@@ -3,7 +3,7 @@ name: CI # Continuous Integration
 on:
   workflow_dispatch:
   push:
-    branches: [main, develop]
+    branches: [main, legacy]
   pull_request:
 
 # simplest example of using the rust-base action

CLAUDE.md

@@ -2,8 +2,8 @@
 
 ## Branches
 
-The `main` branch is in maintenance and bug-fix mode. The `develop` branch
-contains current work.
+The `main` branch contains current work. The `legacy` branch is under
+long-term maintenance and may receive active work.
 
 ## Commands
 

CONTRIBUTING.md

@@ -24,8 +24,8 @@ these standards. It helps us get your PR in faster, and with less work from you.
 
 ### Branching
 
-PRs should target the `develop` branch. The `main` branch is reserved for
-stable releases and receives merges from `develop` at release boundaries.
+PRs should target the `main` branch by default. The `legacy` branch is under
+long-term maintenance and accepts maintenance and backport PRs.
 
 ## Development Basics
 

README.md

@@ -3,8 +3,8 @@
 [![CI](https://github.com/init4tech/node-components/actions/workflows/rust.yml/badge.svg)](https://github.com/init4tech/node-components/actions/workflows/rust.yml)
 [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
 
-> **Note:** The `main` branch is in maintenance and bug-fix mode. The
-> `develop` branch contains current work.
+> **Note:** The `legacy` branch is under long-term maintenance and may receive
+> active work. The `main` branch contains current work.
 
 A collection of components for building the Signet node. These components
 implement core node functionality, but are potentially independently useful.