refactor: ✨ (#418)

* refactor: ✨ move in one commit

Eveything in modules should probably be changed to `exported` defs.
The idea is to move everything first to keep proper history.

* refactor: 📝 add modules readme (wip)

* refactor: ✨ small move

* refactor: 📝 changed nestring, updated modules readme

* refactor: 📝 to document or not to document

* fix: 🐛 themes

replaced the template to use `main` and regenerated them
from lemnos themes.

* Revert "fix: 🐛 themes"

This reverts commit 4918d3633c8d2d81950a0ed0cfd9eb84241bc886.

* refactor: ✨ introduce sourced

- Created a source `root` in which sourcable demos are stored.
  Some might get converted to modules later on.
- Moved some files to bin too.

* fix: 🐛 fehbg.nu

* fix: 🐛 modules/after.nu

* moved some other stuff around

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

modules/virtual_environments/auto-venv/venv_helpers.nu

@@ -0,0 +1,73 @@
+use path_extensions.nu *
+
+def has-sub [
+    folder:    string, 
+    subfolder: string
+] {
+    not (path find-sub $folder $subfolder | is-empty);
+}
+
+def get-env [
+    name:    string
+    default: any
+] {
+    (if ($name in $env) {
+        $env | get $name
+    }
+    else {
+        $default
+    })
+}
+
+export def venv-is-active [] {
+    '__auto_venv' in (overlay list)
+}
+
+
+export def has-entered-venv [
+    after: path,
+] {
+
+    let target = path find-sub $after $env.AUTO_VENV_TRIGGER
+    
+    (if ($target | is-empty) {
+        false
+    }
+    else {
+        # if venv is already active, handle it in "venv swap" hook
+        not (venv-is-active)
+    })
+}
+
+export def has-swapped-venv [
+    after: path,
+] {
+
+    (if not (venv-is-active) {
+        false
+    }
+    else {
+        let target = path find-sub $after $env.AUTO_VENV_TRIGGER
+            
+        (if ($target | is-empty) {
+            false
+        }
+        else {
+            $env.VIRTUAL_ENV != $target
+        })
+
+    })
+}
+
+export def has-exited-venv [
+    after: path,
+] {
+
+    (if not (venv-is-active) {
+        false
+    } 
+    else {
+        not (has-sub $after $env.AUTO_VENV_TRIGGER)
+    })
+}
+