fix: use Skill tool for sync invocation in archive templates (#632)

* fix: use Skill tool for sync invocation in archive templates

Update archive skill templates to properly instruct the AI to use
the Skill tool to invoke sync commands instead of executing command
logic directly.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: use Task tool subagent for sync in archive templates

Skill tool terminates after completion and doesn't return control to the
caller, causing archive to not continue after sync. Changed to spawn a
subagent via Task tool which properly returns control after completion.

Also updated opsx:sync references to openspec-sync-specs for semantic
coherence across templates.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: cheolwanpark

src/core/templates/skill-templates.ts

@@ -2155,7 +2155,7 @@ export function getArchiveChangeSkillTemplate(): SkillTemplate {
    - If changes needed: "Sync now (recommended)", "Archive without syncing"
    - If already synced: "Archive now", "Sync anyway", "Cancel"
 
-   If user chooses sync, execute /opsx:sync logic (use the openspec-sync-specs skill). Proceed to archive regardless of choice.
+   If user chooses sync, use Task tool (subagent_type: "general-purpose", prompt: "Use Skill tool to invoke openspec-sync-specs for change '<name>'. Delta spec analysis: <include the analyzed delta spec summary>"). Proceed to archive regardless of choice.
 
 5. **Perform the archive**
 
@@ -2832,7 +2832,7 @@ export function getOpsxArchiveCommandTemplate(): CommandTemplate {
    - If changes needed: "Sync now (recommended)", "Archive without syncing"
    - If already synced: "Archive now", "Sync anyway", "Cancel"
 
-   If user chooses sync, execute \`/opsx:sync\` logic. Proceed to archive regardless of choice.
+   If user chooses sync, use Task tool (subagent_type: "general-purpose", prompt: "Use Skill tool to invoke openspec-sync-specs for change '<name>'. Delta spec analysis: <include the analyzed delta spec summary>"). Proceed to archive regardless of choice.
 
 5. **Perform the archive**
 
@@ -2926,7 +2926,7 @@ Target archive directory already exists.
 - Don't block archive on warnings - just inform and confirm
 - Preserve .openspec.yaml when moving to archive (it moves with the directory)
 - Show clear summary of what happened
-- If sync is requested, use /opsx:sync approach (agent-driven)
+- If sync is requested, use the Skill tool to invoke \`openspec-sync-specs\` (agent-driven)
 - If delta specs exist, always run the sync assessment and show the combined summary before prompting`
   };
 }