fix: remove .claude nesting from reviewer session dir path

CLAUDE_CONFIG_DIR included .claude suffix, but the container mounts
the parent directory at /home/node/.claude. This caused double nesting:
/home/node/.claude/.claude/CLAUDE.md — SDK never found the prompts.

src/paired-execution-context.ts

@@ -260,7 +260,6 @@ export function preparePairedExecutionContext(args: {
       DATA_DIR,
       'sessions',
       `${group.folder}-reviewer`,
-      '.claude',
     );
     fs.mkdirSync(reviewerSessionDir, { recursive: true });
     envOverrides.CLAUDE_CONFIG_DIR = reviewerSessionDir;