fix(core): Correct CLAUDE_CLI_VERSION to track official Claude Code [skip-version]

CLAUDE_CLI_VERSION should track the official Claude Code CLI version
from npm (@anthropic-ai/claude-code), not the better-ccflare version.

- Reverted CLAUDE_CLI_VERSION from 3.1.0-beta.6 to 2.1.7 (latest from npm)
- Removed incorrect auto-sync logic from pre-push hook
- Updated CLAUDE.md to clarify version update process

The pre-push hook already handles updating CLAUDE_CLI_VERSION from npm.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: tombii

CLAUDE.md

@@ -32,10 +32,11 @@ Always run: `bun run lint && bun run typecheck && bun run format`
 - Skip version bump: Add `[skip-version]` or `[no-version]` to commit message
 
 ## Version Updates
-When bumping version, update in all three files:
+When bumping better-ccflare version, update in both files:
 - `package.json` (root)
 - `apps/cli/package.json`
-- `packages/core/src/version.ts` (CLAUDE_CLI_VERSION constant)
+
+Note: `CLAUDE_CLI_VERSION` in `packages/core/src/version.ts` tracks the official Claude Code CLI version and is auto-updated by the pre-push hook from npm registry.
 
 ## Commands
 

packages/core/src/version.ts

@@ -3,7 +3,7 @@
  */
 
 // Claude CLI version to use in user-agent headers and as fallback
-export const CLAUDE_CLI_VERSION = "3.1.0-beta.6";
+export const CLAUDE_CLI_VERSION = "2.1.7";
 
 // Cache the version to avoid repeated file reads
 let cachedVersion: string | null = null;