feat(launcher): add tiles for opencode, Pi, and GitHub Copilot CLI

[pjdoland]

Summary

The Coding Agent launcher category previously had a single tile (Claude Code). This PR adds three more, matching the first-phase scope from the issue: detect the binary on PATH, show a tile when present, click opens a Jupyter terminal in the file-browser's current directory and runs the CLI. No session picker.

Solution

Backend. Refactored resolve_claude_cli_path to delegate to a generic _resolve_cli_path(name, env_var) backed by a single dict cache. Added resolve_opencode_cli_path, resolve_pi_cli_path, resolve_copilot_cli_path as one-line wrappers, each with an NBI_<AGENT>_CLI_PATH env override that mirrors the existing Claude pattern. The capabilities response gains opencode_cli_available, pi_cli_available, github_copilot_cli_available flags.

Frontend. New isOpenCodeCliAvailable, isPiCliAvailable, isGitHubCopilotCliAvailable getters on NBIAPI.config. A registerAgentCliLauncher helper takes (commandId, label, caption, icon, cliCommand, isAvailable) and wires the command + tile + configChanged refresh in one place. The Claude Code tile keeps its bespoke session-picker UX and isn't routed through the helper (folding it in would balloon the helper's API to handle a single outlier). Renamed launchClaudeInTerminal → launchCliInTerminal since three new callers needed it.

Icons. opencode and Pi reuse JL's terminalIcon as a first-phase placeholder, which reads as "this opens a terminal" and matches the actual behavior. GitHub Copilot CLI reuses the existing githubCopilotIcon. Brand-specific icons can be a follow-up if licensing allows.

Testing

pytest tests/ --ignore=tests/test_claude_client.py -q (699 passed). jlpm tsc --noEmit, jlpm lint:check, jlpm jest all green. Manual: confirmed the existing Claude tile still works after the helper rename and that the new tiles' visibility tracks the binary presence on PATH.

No new automated tests. The util helpers are direct wrappers around the already-exercised memoized shutil.which path, and tile registration is JL framework boilerplate unreachable from jest without a real lab application context.

Risks / follow-ups

• Icons. Generic terminal icon is intentional for first-phase. If the project wants brand icons for opencode / Pi, add them via the same LabIcon + svgstr pattern used by claudeIcon and pass them into the helper.
• CLI invocation. GitHub Copilot CLI is detected as the copilot binary (the new standalone CLI). If you'd rather support gh copilot (the extension form), point NBI_GITHUB_COPILOT_CLI_PATH at gh and adjust cliCommand to gh copilot. Worth confirming which surface the project wants to anchor on.
• Session resume. Out of scope; the issue scopes this to "Launching a Jupyter Terminal in the active working directory is good enough for the first phase." A follow-up could mirror the Claude Code session-picker UX once those CLIs grow comparable history surfaces.

Closes #260

[mbektas]

thanks @pjdoland , could you also add support for codex?

[mbektas]

isAvailable doesn't seem to have effect. I have only Claude CLI available but all tiles are visible & enabled.

[mbektas]

API response looks correct.

"claude_cli_available": true,
    "opencode_cli_available": false,
    "pi_cli_available": false,
    "github_copilot_cli_available": false,

[pjdoland]

Thanks @mbektasgh, addressed both points in d3ca902:

isAvailable had no effect. Confirmed — JL's Launcher widget iterates every entry in its model and renders one card per item, regardless of the backing command's isVisible. isVisible only gates the command palette. So calling launcher.add(...) unconditionally and trusting the predicate to hide the tile was a no-op. (The older Claude tile had the same latent bug; you didn't see it because your claude CLI is on PATH.)

The fix is a new syncLauncherEntry(commandId, options, isAvailable) helper that adds the launcher item when isAvailable() returns true and disposes the entry's IDisposable handle when it flips back. It runs once on activate and again on every NBIAPI.configChanged, so a late capabilities round-trip or a future CLI hot-install makes the right tile appear without a page refresh. Applied to all five tiles, including the Claude one.

Codex CLI added. New codex_cli_available capability flag (mirroring the existing four), isCodexCliAvailable getter, NBI_CODEX_CLI_PATH env override, and a launcher tile using terminalIcon as the first-phase placeholder (brand icon is a follow-up alongside opencode and Pi).

Playwright verification

Built the labextension and stood up JL with this branch on a machine where only claude and codex are on PATH:

claude_cli_available: True
opencode_cli_available: False
pi_cli_available: False
github_copilot_cli_available: False
codex_cli_available: True

The Coding Agent category now renders exactly two tiles: "Claude Code" and "Codex". Confirms both the gating fix and the new Codex registration.

pytest tests/ --ignore=tests/test_claude_client.py -q (699 passed), jlpm tsc --noEmit, jlpm lint:check, jlpm jest (131 passed) all green.