skill: Add Apple container tool reference
Apple's container tool uses different mount syntax from Docker
(--mount type=bind,src=...,dst=... not -v) and has behavioral
quirks that cause errors if Docker patterns are assumed.
Assisted-by: Claude Opus 4.5 (claude-opus-4-5-20250114) via Claude Code
diff --git a/ai/claude/skills/container.md b/ai/claude/skills/container.md
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+---
+name: container
+description: Use when running Apple's container tool on macOS - covers build, run, exec, and image management commands
+---
+
+# Apple Container Tool
+
+macOS container runtime. Not Docker - different syntax for mounts and some flags.
+
+## First-Time Setup
+
+```bash
+container system start # Required before first use, installs kernel
+```
+
+## Quick Reference
+
+| Task | Command |
+|------|---------|
+| Build image | `container build -t name:tag dir/` |
+| Run interactive | `container run -it image` |
+| Run with name | `container run --name mycontainer image` |
+| Run detached | `container run -d --name mycontainer image` |
+| List running | `container list` |
+| List all | `container list -a` |
+| Start stopped | `container start -a container-id` |
+| Stop | `container stop container-id` |
+| Remove | `container rm container-id` |
+| Exec into | `container exec -it container-id bash` |
+| Inspect | `container inspect container-id` |
+
+## Mount Syntax
+
+**Different from Docker.** Uses `--mount` with explicit format:
+
+```bash
+# Bind mount (host path to container path)
+--mount type=bind,src=/host/path,dst=/container/path
+
+# Read-only bind mount
+--mount type=bind,src=/host/path,dst=/container/path,readonly
+
+# tmpfs
+--tmpfs /path
+```
+
+**Not supported:** Docker's `-v /host:/container` shorthand.
+
+## Common Patterns
+
+```bash
+# Build and run interactively
+container build -t myimage:latest . && container run -it --rm myimage:latest
+
+# Run with project mounted
+container run -it --rm \
+ --workdir /project \
+ --mount type=bind,src=$(pwd),dst=/project \
+ myimage:latest
+
+# Named container (persists after exit)
+container run -it --name mycontainer myimage:latest
+# Later: container start -ai mycontainer
+
+# Check if container exists (inspect returns [] for missing, not error)
+[ "$(container inspect mycontainer 2>/dev/null)" != "[]" ] && echo "exists"
+```
+
+## Image Management
+
+```bash
+container image list # List local images
+container image rm image:tag # Remove image
+container image prune # Remove dangling images
+container image prune -a # Remove all unused images
+```
+
+## Gotchas
+
+- **No `-a` for list by default** - stopped containers hidden without `container list -a`
+- **Mount syntax** - must use `--mount type=bind,src=...,dst=...` not `-v`
+- **System start required** - run `container system start` before first use
+- **Names are IDs** - `--name` sets the container ID, not a separate alias
+- **Inspect returns `[]` for missing** - doesn't error like Docker, check output not exit code