feat(nushell): add cached nu_scripts completions bootstrap

- add pj completion command to clone/update nu_scripts cache

- load fixed custom-completions for git/ssh/cargo/uv/rustup from cache

- ignore nushell/cache contents in git while keeping placeholder .gitignore

- source pj_completions at startup and align prompt indicators/newline behavior

nushell/modules/pj_prompt.nu

@@ -605,7 +605,8 @@ def _pj_left_prompt [] {
     for m in $lang_parts {
         $out = $"($out)($m)"
     }
-    $out = $"\n($out)($time_part)($duration_part)\n"
+    let prompt_newline = if (($nu.os-info.name | str downcase) == "windows") { "\n\r" } else { "\n" }
+    $out = $"($prompt_newline)($out)($time_part)($duration_part)($prompt_newline)"
     $out
 }
 
@@ -626,8 +627,12 @@ export-env {
         PROMPT_INDICATOR: {||
             _pj_prompt_indicator
         }
-        PROMPT_INDICATOR_VI_INSERT: ""
-        PROMPT_INDICATOR_VI_NORMAL: ""
+        PROMPT_INDICATOR_VI_INSERT: {||
+            _pj_prompt_indicator
+        }
+        PROMPT_INDICATOR_VI_NORMAL: {||
+            _pj_prompt_indicator
+        }
         PROMPT_COMMAND: {||
             _pj_left_prompt
         }