Add setup notes and Claude Code guidance for mac-mini LLM host

README: document VNC/screen-sharing and record the macOS 26 gotcha
that the Screen Sharing authorization switch is GUI/MDM-only —
launchctl/kickstart/SRP/access-group all fail. Add CLAUDE.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,28 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## What this repo is
+
+Operational notes (not code) for a remote LLM host: `mac-mini.internal.lotimmy.com` (Apple M4, 24 GB, arm64). `README.md` is the source of truth for hardware specs, installed tools, downloaded models, and the full command reference — read it before acting.
+
+There is no build/lint/test — actual work runs on the remote host over SSH, so most "commands" are things to run *there*, not locally.
+
+## Working on the remote host
+
+- Connect by hostname only: `ssh mac-mini.internal.lotimmy.com`. Connecting by IP (`192.168.88.15`) fails host-key verification.
+- **Homebrew is not in the non-interactive SSH PATH.** Every remote command must load it first, or `brew`/`llmfit`/`llama-*` will be `command not found`:
+  ```bash
+  ssh mac-mini.internal.lotimmy.com 'eval "$(/opt/homebrew/bin/brew shellenv)" && <command>'
+  ```
+
+## Running llama.cpp (b8680 on this host)
+
+- Single-shot inference → `llama-completion`. Interactive chat → `llama-cli`. **Do not pass `-no-cnv`** (unsupported in b8680; it prints an error and drops into chat anyway).
+- Gemma 4 models **require `--jinja`** or `llama-completion` throws `this custom template is not supported`.
+- Always pass `-ngl 999` to force all layers onto the GPU; auto-detection can silently fall back to CPU (~5× slower).
+- **Never pipe `llama-cli` output to `tail`** — interactive mode keeps printing `> ` prompts, so you see nothing and stdout balloons to GB. Use `llama-completion`, or redirect to a file and read it.
+
+## When editing this repo
+
+It's documentation. Keep the README's existing structure (踩雷紀錄 = gotchas log); append new gotchas there rather than scattering them.