fix: save /plan output in workspace (#1381)

skills/software-development/plan/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: plan
-description: Plan mode for Hermes — inspect context, write a markdown plan, save it under $HERMES_HOME/plans, and do not execute the work.
+description: Plan mode for Hermes — inspect context, write a markdown plan into the active workspace's `.hermes/plans/` directory, and do not execute the work.
 version: 1.0.0
 author: Hermes Agent
 license: MIT
@@ -22,7 +22,7 @@ For this turn, you are planning only.
 - Do not edit project files except the plan markdown file.
 - Do not run mutating terminal commands, commit, push, or perform external actions.
 - You may inspect the repo or other context with read-only commands/tools when needed.
-- Your deliverable is a markdown plan saved to `$HERMES_HOME/plans`.
+- Your deliverable is a markdown plan saved inside the active workspace under `.hermes/plans/`.
 
 ## Output requirements
 
@@ -42,10 +42,12 @@ If the task is code-related, include exact file paths, likely test targets, and
 ## Save location
 
 Save the plan with `write_file` under:
-- `$HERMES_HOME/plans/YYYY-MM-DD_HHMMSS-<slug>.md`
+- `.hermes/plans/YYYY-MM-DD_HHMMSS-<slug>.md`
+
+Treat that as relative to the active working directory / backend workspace. Hermes file tools are backend-aware, so using this relative path keeps the plan with the workspace on local, docker, ssh, modal, and daytona backends.
 
 If the runtime provides a specific target path, use that exact path.
-If not, create a sensible timestamped filename yourself.
+If not, create a sensible timestamped filename yourself under `.hermes/plans/`.
 
 ## Interaction style