Insert a working repeat block instead of its description

The placeholder chooser showed repeat blocks as "{{#claims}} … {{/claims}}" and
inserted exactly that on double-click -- the ellipsis is a label, so the saved
template rendered a literal "…" per claim instead of the claim.

Chooser rows are data now: each carries the text it reads as and, separately,
the snippet it inserts. A block contributes a complete, ready-to-edit block with
a sample line built from its own placeholders, and lands on a line of its own
when the cursor sits behind existing text.

Covered from both sides: the snippets are checked against the template validator
and renderer, and a UI test drives the real dialog -- insert, save, send -- and
asserts the mail carries actual claim lines. The Tk tests share one root (the
icon library binds its images to the first one) and skip without a display.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/ccma/ui/options_dialog.py

@@ -11,6 +11,7 @@ from ccma.domain.mail_templates import (
     MAIL_TEMPLATES,
     MailTemplateError,
     default_mail_template,
+    placeholder_entries,
     template_spec,
 )
 from ccma.domain.models import HOUSEKEEPER_MEMBER_FIELD_LABELS
@@ -81,6 +82,7 @@ class OptionsDialog(tk.Toplevel):
         self.mail_template_var = tk.StringVar(value=MAIL_TEMPLATES[0].label)
         self.mail_template_subject_var = tk.StringVar()
         self.mail_template_hint_var = tk.StringVar()
+        self.mail_template_snippets: dict[str, str] = {}
         self.title("Optionen")
         self.transient(master.winfo_toplevel())
         self.grab_set()
@@ -1031,18 +1033,15 @@ class OptionsDialog(tk.Toplevel):
         self.mail_template_body.delete("1.0", "end")
         self.mail_template_body.insert("1.0", body)
         self.mail_template_placeholders.delete(*self.mail_template_placeholders.get_children())
-        for name, description in spec.placeholders:
-            self.mail_template_placeholders.insert(
-                "", "end", values=(f"{{{{{name}}}}}", description)
+        # The row text is a readable label; what actually gets inserted is the entry's
+        # snippet, which for a repeat block is the whole block and not its description.
+        self.mail_template_snippets = {}
+        for entry in placeholder_entries(key):
+            label = f"    {entry.label}" if entry.indented else entry.label
+            row = self.mail_template_placeholders.insert(
+                "", "end", values=(label, entry.description)
             )
-        for name, description, items in spec.blocks:
-            self.mail_template_placeholders.insert(
-                "", "end", values=(f"{{{{#{name}}}}} … {{{{/{name}}}}}", description)
-            )
-            for item_name, item_description in items:
-                self.mail_template_placeholders.insert(
-                    "", "end", values=(f"    {{{{{item_name}}}}}", item_description)
-                )
+            self.mail_template_snippets[row] = entry.snippet
 
     def _capture_mail_template(self) -> None:
         if not hasattr(self, "mail_template_body"):
@@ -1081,10 +1080,19 @@ class OptionsDialog(tk.Toplevel):
         selected = self.mail_template_placeholders.selection()
         if not selected:
             return
-        value = str(self.mail_template_placeholders.item(selected[0], "values")[0]).strip()
-        self.mail_template_body.insert("insert", value)
+        snippet = self.mail_template_snippets.get(selected[0])
+        if not snippet:
+            return
+        # A multi-line block only works on lines of its own, so it starts on a fresh
+        # one instead of being appended to whatever the cursor sat behind.
+        if "\n" in snippet.strip() and not self._mail_cursor_at_line_start():
+            snippet = "\n" + snippet
+        self.mail_template_body.insert("insert", snippet)
         self.mail_template_body.focus_set()
 
+    def _mail_cursor_at_line_start(self) -> bool:
+        return str(self.mail_template_body.index("insert")).split(".")[1] == "0"
+
     def _save_mail_templates(self) -> None:
         self._capture_mail_template()
         for key, (subject, body) in self.mail_template_edits.items():