fix: properly quote base and pm_agent in write_index calls

When base or pm_agent are not null, they need to be quoted with escaped quotes ("") in write_index calls.
This fixes 'write_index would create malformed JSON' error during init.

skills/kugetsu/scripts/kugetsu-index.sh

@@ -50,7 +50,11 @@ set_base_in_index() {
     if [ "$session_id" = "null" ]; then
         write_index "null" "$pm_agent" "$issues"
     else
-        write_index "\"$session_id\"" "$pm_agent" "$issues"
+        if [ "$pm_agent" = "null" ]; then
+            write_index "\"$session_id\"" "null" "$issues"
+        else
+            write_index "\"$session_id\"" "\"$pm_agent\"" "$issues"
+        fi
     fi
 }
 
@@ -63,7 +67,11 @@ set_pm_agent_in_index() {
     if [ "$session_id" = "null" ]; then
         write_index "$base" "null" "$issues"
     else
-        write_index "$base" "\"$session_id\"" "$issues"
+        if [ "$base" = "null" ]; then
+            write_index "null" "\"$session_id\"" "$issues"
+        else
+            write_index "\"$base\"" "\"$session_id\"" "$issues"
+        fi
     fi
 }
 
@@ -79,7 +87,19 @@ add_issue_to_index() {
     
     issues=$(python3 -c "import sys, json; d=json.load(sys.stdin); d['$issue_ref']='$session_file'; print(json.dumps(d))" <<< "$issues")
     
-    write_index "$base" "$pm_agent" "$issues"
+    if [ "$base" = "null" ]; then
+        if [ "$pm_agent" = "null" ]; then
+            write_index "null" "null" "$issues"
+        else
+            write_index "null" "\"$pm_agent\"" "$issues"
+        fi
+    else
+        if [ "$pm_agent" = "null" ]; then
+            write_index "\"$base\"" "null" "$issues"
+        else
+            write_index "\"$base\"" "\"$pm_agent\"" "$issues"
+        fi
+    fi
 }
 
 remove_issue_from_index() {
@@ -93,7 +113,19 @@ remove_issue_from_index() {
     
     issues=$(python3 -c "import sys, json; d=json.load(sys.stdin); d.pop('$issue_ref', None); print(json.dumps(d))" <<< "$issues")
     
-    write_index "$base" "$pm_agent" "$issues"
+    if [ "$base" = "null" ]; then
+        if [ "$pm_agent" = "null" ]; then
+            write_index "null" "null" "$issues"
+        else
+            write_index "null" "\"$pm_agent\"" "$issues"
+        fi
+    else
+        if [ "$pm_agent" = "null" ]; then
+            write_index "\"$base\"" "null" "$issues"
+        else
+            write_index "\"$base\"" "\"$pm_agent\"" "$issues"
+        fi
+    fi
 }
 
 validate_issue_ref() {