feat(sdk): pluginRoot officiel exposé dans activate(ctx) — #285 (src/runtime: champ pluginRoot = racine du package installé; docs activation-context/commands-and-feedback/services/manifest réécrits du constat d'absence vers le contrat d'usage officiel — runCommand reste project-scoped, pluginRoot utilisable dans command/args, substitution manifest ${pluginRoot}/${appDataDir} inchangée pour mcpServers; exemple hello-plugin: script packagé scripts/hello-task.mjs consommé via ctx.pluginRoot, packaging étendu; QA verte: npm run check — build, typecheck:examples, package:hello-plugin, artefact zip vérifié)

docs/services.md

@@ -37,12 +37,24 @@ Key APIs:
 Use `runCommand()` only after preconditions are satisfied. `ownerAgentId` must be
 a real agent id when work belongs to an agent workflow.
 
-`runCommand()` is project/workspace scoped. Its `cwd` option is a relative path
-under the project root, and `command`/`args` are not resolved against the
-calling plugin's package. The SDK does not currently provide a public
-`pluginRoot` or package-path resolver for runtime command handlers. Packaged
-scripts cannot be launched through `runCommand()` by referring to their
-package-relative path.
+`runCommand()` keeps its `cwd` project/workspace scoped: `cwd` must be a relative
+path under the project root. The host does not implicitly resolve `command` or
+`args` against the plugin package. Use the absolute `ctx.pluginRoot` supplied at
+activation time to construct an explicit path to a packaged script, and pass
+that path as `command` or as an argument to its interpreter. Treat package files
+as read-only.
+
+```ts
+const script = `${ctx.pluginRoot.replace(/[\\/]+$/, "")}/scripts/check.mjs`;
+await ctx.services.tasks.runCommand({
+  projectId,
+  ownerAgentId,
+  label: "Run packaged check",
+  command: "node",
+  args: [script],
+  cwd: "."
+});
+```
 
 ## Tooling