CLI loads harness spec 3.0.0-draft; the show tool over the link

The spec's version may be a pre-release (3.0.0-draft). Every tool file is
loaded, with the new fields `sessions`, `requires`, `unavailable` and
`confirm`; the CLI's tools are those not the server's alone and offered in an
agent session (forCli) — a chat's own tools over the server's tree (mkdir, mv,
rm, search, python, the forge verbs) are not built in. blocks/context.md is
known; blocks/workspace.md is the server's alone.

show is built in with `requires: display`: offered only in a session a client
opened over the link when that client said `show: true` (capability `show`);
the device reads the file (at most 1 MB) and sends it with `_lembas/show`.
The harness tests now say 3.0.0's split of tools instead of "the execution
tools are the CLI's alone".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/acp.test.ts

@@ -233,7 +233,7 @@ test("the terminal: a real shell through the link, only where remote.terminal sa
   config(fake.url)
   const root = project()
   const off = await client({ roots: [root], maxMode: "edit", approvalTimeoutMs: 50, requireTrust: true })
-  expect(off.init._meta.lembas.capabilities).toEqual(["directories", "configure", "steer", "sessions", "status", "delete", "compact", "title", "files", "commands", "attachments", "ask", "plan", "model", "turns", "context", "library", "prototypes", "plan_state", "rewind", "jobs"])
+  expect(off.init._meta.lembas.capabilities).toEqual(["directories", "configure", "steer", "sessions", "status", "delete", "compact", "title", "files", "commands", "attachments", "ask", "plan", "model", "turns", "context", "library", "prototypes", "plan_state", "rewind", "jobs", "show"])
   await expect(off.c.request("_lembas/terminal/open", { cwd: root })).rejects.toThrow("remote.terminal is off")
 
   const { c, init } = await client({ roots: [root], maxMode: "edit", approvalTimeoutMs: 50, requireTrust: true, terminal: true })