feat(skills): add 'hermes skills reset' to un-stick bundled skills (#11468)

When a user edits a bundled skill, sync flags it as user_modified and
skips it forever. The problem: if the user later tries to undo the edit
by copying the current bundled version back into ~/.hermes/skills/, the
manifest still holds the old origin hash from the last successful
sync, so the fresh bundled hash still doesn't match and the skill stays
stuck as user_modified.

Adds an escape hatch for this case.

  hermes skills reset <name>
      Drops the skill's entry from ~/.hermes/skills/.bundled_manifest and
      re-baselines against the user's current copy. Future 'hermes update'
      runs accept upstream changes again. Non-destructive.

  hermes skills reset <name> --restore
      Also deletes the user's copy and re-copies the bundled version.
      Use when you want the pristine upstream skill back.

Also available as /skills reset in chat.

- tools/skills_sync.py: new reset_bundled_skill(name, restore=False)
- hermes_cli/skills_hub.py: do_reset() + wired into skills_command and
  handle_skills_slash; added to the slash /skills help panel
- hermes_cli/main.py: argparse entry for 'hermes skills reset'
- tests/tools/test_skills_sync.py: 5 new tests covering the stuck-flag
  repro, --restore, unknown-skill error, upstream-removed-skill, and
  no-op on already-clean state
- website/docs/user-guide/features/skills.md: new 'Bundled skill updates'
  section explaining the origin-hash mechanic + reset usage

hermes_cli/main.py

@@ -5600,6 +5600,25 @@ Examples:
     skills_uninstall = skills_subparsers.add_parser("uninstall", help="Remove a hub-installed skill")
     skills_uninstall.add_argument("name", help="Skill name to remove")
 
+    skills_reset = skills_subparsers.add_parser(
+        "reset",
+        help="Reset a bundled skill — clears 'user-modified' tracking so updates work again",
+        description=(
+            "Clear a bundled skill's entry from the sync manifest (~/.hermes/skills/.bundled_manifest) "
+            "so future 'hermes update' runs stop marking it as user-modified. Pass --restore to also "
+            "replace the current copy with the bundled version."
+        ),
+    )
+    skills_reset.add_argument("name", help="Skill name to reset (e.g. google-workspace)")
+    skills_reset.add_argument(
+        "--restore", action="store_true",
+        help="Also delete the current copy and re-copy the bundled version",
+    )
+    skills_reset.add_argument(
+        "--yes", "-y", action="store_true",
+        help="Skip confirmation prompt when using --restore",
+    )
+
     skills_publish = skills_subparsers.add_parser("publish", help="Publish a skill to a registry")
     skills_publish.add_argument("skill_path", help="Path to skill directory")
     skills_publish.add_argument("--to", default="github", choices=["github", "clawhub"], help="Target registry")