cli: up, ls, open, close

Slice 2 of docs/cli-design.md. The commands read the world (discovery +
list-tabs), compute a plan, then apply it -- never mutating while walking, which
is how `up` stays idempotent.

  sl0ppij.ts   process wrapper; every piece of state comes back out of
               list-tabs/list-panes, so there is nothing to desync
  layout.ts    composes the tab node around a project's fragment
  root.ts      root resolution, session naming, the root registry
  workspace.ts up / ls / open / close
  index.ts     dispatch + the fail-open wrapper

Four things this turned up that reading the code would not have:

  - `attach --create-background` fails with "There is no active session!" when
    the caller is itself inside a session -- which sl0ppi almost always is,
    being run from the user's daily-driver terminal. Session creation now runs
    with the SL0PPIJ*/ZELLIJ* markers stripped: we are creating a new detached
    session, not nesting.

  - falling open by passing our own argv to sl0ppij just produces "unrecognized
    subcommand: up" and still leaves the user without a terminal. Our verbs and
    flags are stripped first, so what is handed over is something sl0ppij
    actually understands.

  - attaching panics in the client when stdin is not a tty, so `up` from a
    script or CI step died. It now reports the session is ready and exits.

  - a start_suspended pane reports `is_held`, not `exited`. Conflating them made
    `ls` claim every agent was running when none had started. Plugin panes (the
    status bar, the link handler) also inflated pane counts and are now excluded
    as chrome.

Index conventions were verified against a live session rather than inferred,
because guessing closes the wrong tab: list-tabs `position` and
`close-tab --tab-id` are 0-based, `go-to-tab` is 1-based, and closing renumbers
every tab after it, so batched closes run in descending position order.

Verified end to end against a real session (three projects, one shipping a
custom fragment): up creates the session with all tabs and their purposes; up
again reports "up to date" with tabs unchanged; ls reports panes and
agent:suspended correctly; open creates-and-focuses and resolves unique
prefixes; close removes a tab; deleting a project auto-closes its tab; and with
the root itself missing, nothing is closed at all.

64 tests green.

1 files changed, 95 insertions, 0 deletions

diff --git a/cli/test/cli.test.ts b/cli/test/cli.test.ts
new file mode 100644
index 0000000..464ade4
--- /dev/null
+++ b/cli/test/cli.test.ts
@@ -0,0 +1,95 @@
+import { describe, expect, test } from "bun:test";
+import { parseArgs, passthroughArgs } from "../src/index.ts";
+import { agentStateOf } from "../src/commands/workspace.ts";
+import { withoutSessionEnv } from "../src/core/sl0ppij.ts";
+
+describe("parseArgs", () => {
+  test("defaults to up", () => {
+    expect(parseArgs([]).command).toBe("up");
+    expect(parseArgs(["--root", "/x"]).command).toBe("up");
+  });
+
+  test("recognises the verbs", () => {
+    for (const verb of ["up", "ls", "open", "close", "help"]) {
+      expect(parseArgs([verb]).command).toBe(verb);
+    }
+  });
+
+  test("keeps the project name as an argument", () => {
+    const args = parseArgs(["open", "myproj", "--root", "/x"]);
+    expect(args.command).toBe("open");
+    expect(args.rest).toEqual(["myproj"]);
+    expect(args.rootFlag).toBe("/x");
+  });
+
+  test("accepts both flag spellings", () => {
+    expect(parseArgs(["--root=/x"]).rootFlag).toBe("/x");
+    expect(parseArgs(["--depth=3"]).depth).toBe(3);
+    expect(parseArgs(["--depth", "2"]).depth).toBe(2);
+    expect(parseArgs(["-n"]).dryRun).toBe(true);
+  });
+
+  test("a bad depth falls back to 1 rather than NaN", () => {
+    expect(parseArgs(["--depth", "banana"]).depth).toBe(1);
+  });
+});
+
+// Falling open is only useful if what we hand over is something sl0ppij
+// understands. Passing `up` through just yields "unrecognized subcommand" and
+// still leaves the user without a terminal.
+describe("passthroughArgs", () => {
+  test("strips our verbs and flags", () => {
+    expect(passthroughArgs(["up", "--root", "/x"])).toEqual([]);
+    expect(passthroughArgs(["ls", "--depth=2"])).toEqual([]);
+    expect(passthroughArgs(["open", "proj", "-n"])).toEqual(["proj"]);
+  });
+
+  test("keeps arguments sl0ppij would understand", () => {
+    expect(passthroughArgs(["attach", "mysession"])).toEqual(["attach", "mysession"]);
+    expect(passthroughArgs(["--root", "/x", "list-sessions"])).toEqual(["list-sessions"]);
+  });
+
+  test("only the leading verb is dropped", () => {
+    // `sl0ppij action ... close` style words further along must survive
+    expect(passthroughArgs(["action", "close-tab"])).toEqual(["action", "close-tab"]);
+  });
+});
+
+describe("agentStateOf", () => {
+  // A start_suspended pane reports is_held, not exited: the command is staged
+  // but has never run. Conflating the two made `ls` claim twelve agents were
+  // running when none were.
+  test("held means suspended", () => {
+    expect(agentStateOf({ is_held: true })).toBe("suspended");
+  });
+  test("exited means exited", () => {
+    expect(agentStateOf({ exited: true })).toBe("exited");
+  });
+  test("neither means running", () => {
+    expect(agentStateOf({})).toBe("running");
+  });
+  test("absent means none", () => {
+    expect(agentStateOf(undefined)).toBe("none");
+  });
+});
+
+describe("withoutSessionEnv", () => {
+  // `attach --create-background` fails with "There is no active session!" when
+  // the caller is inside a session, and sl0ppi is nearly always run from one.
+  test("drops both spellings of the session markers", () => {
+    const cleaned = withoutSessionEnv({
+      ZELLIJ: "0",
+      ZELLIJ_SESSION_NAME: "inventive-drum",
+      SL0PPIJ: "0",
+      SL0PPIJ_SESSION_NAME: "dev",
+      SL0PPIJ_PANE_ID: "3",
+      PATH: "/usr/bin",
+    });
+    expect(cleaned.ZELLIJ).toBeUndefined();
+    expect(cleaned.ZELLIJ_SESSION_NAME).toBeUndefined();
+    expect(cleaned.SL0PPIJ).toBeUndefined();
+    expect(cleaned.SL0PPIJ_SESSION_NAME).toBeUndefined();
+    expect(cleaned.SL0PPIJ_PANE_ID).toBeUndefined();
+    expect(cleaned.PATH).toBe("/usr/bin");
+  });
+});