fix(debug): shortened js-debug install hint to the repo download

- Runtime error now just says to download vscode-js-debug from its GitHub repo;
  tarball recipe, extract path, env var, and Mason detail stay in docs/tools/debug.md.

docs/tools/debug.md

@@ -330,9 +330,8 @@ Example `.omp/dap.json`:
 
 ## Notes
 - `packages/coding-agent/src/prompts/tools/debug.md` tells the model only one active root session is supported. Adapter-requested child sessions belong to that root tree.
-- The default JavaScript/TypeScript adapter runs vscode-js-debug's `dapDebugServer.js` over TCP. It is **not** an npm package — `npm i -g js-debug-adapter` 404s (`js-debug-adapter` is the omp adapter id, not an installable package). Install `dapDebugServer.js` one of these ways; the first two are auto-discovered by `resolveJsDebugServerPath()` in `packages/coding-agent/src/dap/config.ts`:
-  - Mason (`:MasonInstall js-debug-adapter`) → discovered at `~/.local/share/nvim/mason/packages/js-debug-adapter/js-debug/src/dapDebugServer.js`.
-  - Standalone release tarball, extracted so `dapDebugServer.js` lands at `~/.local/opt/js-debug/src/dapDebugServer.js`:
+- The default JavaScript/TypeScript adapter runs vscode-js-debug's `dapDebugServer.js` over TCP. Install it one of these ways; the first and last are auto-discovered by `resolveJsDebugServerPath()` in `packages/coding-agent/src/dap/config.ts`. (Don't try `npm i -g js-debug-adapter` — it 404s; `js-debug-adapter` is the omp adapter id, not an npm package.)
+  - Release tarball, extracted so `dapDebugServer.js` lands at `~/.local/opt/js-debug/src/dapDebugServer.js`:
     ```sh
     curl -sL -o js-debug-dap.tar.gz \
       https://github.com/microsoft/vscode-js-debug/releases/download/v1.117.0/js-debug-dap-v1.117.0.tar.gz
@@ -340,6 +339,7 @@ Example `.omp/dap.json`:
     ```
     Replace `v1.117.0` with the latest tag from the [releases page](https://github.com/microsoft/vscode-js-debug/releases).
   - Any other location via `JS_DEBUG_DAP_SERVER=<path-to-dapDebugServer.js>`.
+  - Neovim users with Mason: `:MasonInstall js-debug-adapter` → discovered at `~/.local/share/nvim/mason/packages/js-debug-adapter/js-debug/src/dapDebugServer.js`.
 - The adapter runs under `node` if on `PATH`, otherwise under the omp host (Bun); `resolveDefaultJsDebugAdapter()` falls back to `process.execPath`, so a Bun-only setup is supported.
 - `configurationDone` is sent automatically during root and child launch/attach handshakes and lazily before later requests if the initial handshake did not complete.
 - `startDebugging` reverse requests create recursive child sessions on the same TCP server; a stopped child becomes the target for thread-level actions.

packages/coding-agent/src/tools/debug.ts

@@ -505,7 +505,7 @@ const ADAPTER_UNAVAILABLE_MESSAGES: Readonly<Record<string, string>> = {
 	dlv: "adapter 'dlv' is not available: install with 'go install github.com/go-delve/delve/cmd/dlv@latest'",
 	rdbg: "adapter 'rdbg' is not available: install with 'gem install debug'",
 	"js-debug-adapter":
-		"adapter 'js-debug-adapter' is not available: vscode-js-debug is not an npm package — install via Mason (`:MasonInstall js-debug-adapter`), extract the release tarball (https://github.com/microsoft/vscode-js-debug/releases) under ~/.local/opt, or set JS_DEBUG_DAP_SERVER to dapDebugServer.js",
+		"adapter 'js-debug-adapter' is not available: download it from https://github.com/microsoft/vscode-js-debug",
 };
 
 const ADAPTER_CANONICAL_COMMANDS: Readonly<Record<string, string>> = {

packages/coding-agent/test/debug/dap-launch-failures.test.ts

@@ -882,7 +882,7 @@ describe("DebugTool launch validation", () => {
 				const tool = new DebugTool(session);
 
 				await expect(tool.execute("call", { action: "launch", program: "main.js" })).rejects.toThrow(
-					/Mason.*release tarball.*JS_DEBUG_DAP_SERVER/,
+					/download.*github\.com\/microsoft\/vscode-js-debug/,
 				);
 			} finally {
 				await removeWithRetries(cwd);