docs: describe deletes that go to the trash

A new page, `doc/trash.md`, covers what a delete does now: where a path lands on
each platform, what is still deleted outright (an explicit `permanent=true`, a
host that cleared `[trash]`, scratch paths under the OS temp dir, the
`copy_path` / `move_path` overwrite, the temporary-workspace cleanup), what
happens when a trashing is refused — the file stays and the error says how to
delete it on purpose — and the two things the trash cannot help with: a shell
`rm` and anything a plugin or MCP server does on its own.

`[trash]` joins the example config and the README snippet, the README gains the
one-paragraph version, `AGENTS.md` the tool/config notes (including the confirm
wording a delete now uses), and the default tool playbook tells the model that
`delete_path` is undoable and what `permanent=true` costs.

README.md

@@ -180,6 +180,10 @@ max_context_tokens = 200000
 # channels = ["auto"]             # auto | desktop | terminal
 # actions = true                  # allow / deny / review buttons + reply field
 # include_reason = false          # off: the reason may name a command or URL
+
+# Deletes: `delete_path` moves the path to the system trash. See doc/trash.md.
+# [trash]
+# enabled = true                  # false = a delete is final again
 ```
 
 Per-provider **`timeout`** is passed to the HTTP session for chat/completions, Responses, and `GET /models`. A single number sets one timeout; `{ connect, read }` splits TCP/TLS setup vs idle wait between response bytes (SSE can run longer than `read` while chunks keep arriving). Tool/process timeouts (`run_argv`, PTY, policy confirm) are separate.
@@ -204,6 +208,8 @@ Third-party **plugins**: install a package that declares `project.entry-points."
 
 **Notifications while a prompt waits**: a turn stops at a confirm, a directory-access request or an `ask_user_*` question, so if you walked away you only find out on your return. After `[notify].grace_seconds` (5s) the prompt is announced — with **Allow once / Deny / Go to terminal** buttons for a confirmation and a reply field for a question, where the platform renders them — and the answer is taken as if typed at the terminal (never as a session grant). The desktop channel needs the optional extra (`pip install 'plyngent[notify]'`); without it the CLI writes an OSC 777 / OSC 9 escape sequence to `/dev/tty`, which every modern terminal turns into a native notification with no dependency at all. Answering at the terminal inside the grace period stays silent, `[notify].include_reason` keeps the reason line (a command, argv or URL) out by default, and no channel can break a prompt: a missing extra or a refusing desktop falls through to the next one. Details: [doc/notifications.md](doc/notifications.md).
 
+**Deletes go to the trash**: `delete_path` moves the path into the desktop's own trash — the freedesktop trash on Linux, the Finder trash on macOS, the Recycle Bin on Windows — so a delete the agent made on its own can be undone from the file manager you already use. That matters because the tool is YOLO-tagged: under `--yes` / `/yolo on` it runs without a confirmation. Ask for the old behaviour with `permanent=true`, or turn it off for every call with `[trash] enabled = false`. Paths under the system temp directory are scratch and are deleted outright, a trashing that fails (a volume with no usable trash directory, a broken install) leaves the file alone and says so instead of deleting it, and a shell `rm` never uses the trash. Details: [doc/trash.md](doc/trash.md).
+
 **MCP servers** (Model Context Protocol over stdio): define servers under `[mcp.servers.<name>]` (`command` + `args`, optional `env`/`cwd`/`timeout`/`read_only`) and their tools become agent tools namespaced `mcp__<server>__<tool>` (LOCAL tags; `read_only = true` also marks them READ_ONLY, eligible for `/btw --tools=read`). Names in `[mcp].disable` stay disconnected. A server may also return optional `instructions` (usage guidance) in its MCP `initialize` response; when tools are on those are folded into the agent system prompt as `MCP server <name> instructions:` blocks (`[agent] mcp_instructions = false` disables), and `/mcp` previews them. In the REPL, `/mcp` lists per-server status and tool counts; `/mcp reconnect` re-reads the config file and restarts every enabled server (adopts newly added ones).
 
 Supported provider presets today: