Fixes #108608

What Problem This Solves

Fixes an issue where users opening a local Claude Code catalog session in Control UI would get Error: claude native binary not installed. when their login shell selected Anthropic's failed npm placeholder even though a working native Claude installation was available.

Why This Change Was Made

The Anthropic plugin now recognizes the exact failed npm placeholder, including npm-style cross-platform command shims, without executing it. It prefers the native installer at ~/.local/bin/claude, then the newest Claude Desktop-managed binary on macOS, while preserving the user's login-shell PATH; if no working replacement exists, terminal capability is hidden instead of launching a guaranteed failure.

User Impact

Open in terminal now resumes Claude sessions with a working native executable on affected machines. Machines that only have the failed npm placeholder no longer offer a terminal action that cannot succeed.

Evidence

• Before: live verification reproduced the exact npm-placeholder error from the selected login-shell claude; the Claude Desktop native executable on the same host returned 2.1.209 (Claude Code).
• End to end: an isolated Gateway on the affected macOS host exposed a synthetic Claude session in Control UI. Opening its context menu and choosing Open in terminal created a connected terminal, and the matching host process was ~/Library/Application Support/Claude/claude-code/2.1.209/claude.app/Contents/MacOS/claude --resume 10860800-0000-4000-8000-000000000001 rather than /opt/homebrew/bin/claude.
• Negative probe: removing the isolated native executable and restarting the Gateway changed Open in terminal to disabled with Terminal opening is unavailable for this session.
• Focused regression: node scripts/run-vitest.mjs extensions/anthropic/session-catalog.test.ts — 21/21 passed.
• Changed-surface proof: Blacksmith Testbox run — format, lint, extension/test typechecks, plugin boundaries, import cycles, and policy guards passed.
• Autoreview: clean after accepting and fixing the package-manager shim portability finding.