Clarify Anchor v1 as current stable, v2 as release candidate

[mikemaccana]

Summary

Updated documentation throughout the repository to accurately reflect the current state of Anchor versions: Anchor v1 (1.2.0) is the current stable release, while Anchor v2 (2.0.0-rc.1) is a release candidate for the next major version.

Key Changes

• README.md: Reordered Anchor v1 and v2 references to list v1 first as the current major version, updated descriptions to clarify v1 as stable and v2 as unreleased
• CI badges: Reordered workflow badges in README to show Anchor v1 first
• Example links: Updated all example links throughout README to list Anchor v1 before Anchor v2 (affects finance examples: escrow, lending, order-book, token-swap, prop-amm, vault-strategy, betting-market, options, perpetual-futures, token-fundraiser; and basics examples: hello-solana, account-data, counter, favorites, checking-accounts, close-account, create-account, and others)
• Anchor v1 README headers: Updated all anchor-v1/README.md files across all examples to describe v1 as "on Anchor 1.2.0, the current stable Anchor release" instead of "kept for programs staying on the Anchor v1 LTS line"
• CONTRIBUTING.md: Reordered description of anchor-v1/ and anchor/ directories to list v1 first as current stable
• CHANGELOG.md: Added new entry documenting this clarification
• llms.txt: Updated to reference Anchor 1.2 instead of 1.1

Implementation Details

The changes are purely documentation updates with no code logic modifications. All example links and references maintain their functionality while presenting a more accurate representation of the Anchor ecosystem's current state.

https://claude.ai/code/session_01CjfAr6kD3AS9ihsQZEGzTt