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/commands-and-feedback.md

@@ -43,9 +43,10 @@ Check preconditions before calling `runCommand()`:
 - `ownerAgentId` is a real agent id when the work is owned by an agent workflow.
   Do not use all-zero placeholders in production.
 - `cwd` is relative to the project root.
-- `command`, `args` and `cwd` do not resolve package-relative plugin resources.
-  Do not use `runCommand()` to launch scripts shipped inside the plugin package;
-  there is no public runtime `pluginRoot` path in `activate(ctx)`.
+- `command` and `args` do not resolve package-relative plugin resources
+  implicitly. Build an explicit absolute script path from `ctx.pluginRoot` when
+  launching read-only files shipped in the installed package.
+- Do not use `ctx.pluginRoot` as `cwd`; `cwd` remains relative to the project root.
 - `command` and `args` are separate values. Do not shell-join user input.
 
 If any required precondition fails, return a skipped result: