Lighten the comment load

Drops porting-history narratives (dodrenett), superseded-behavior
explanations, and restatements of what the next line does. Constraint
notes (fail-closed policies, CAS semantics, cascade behavior, id
uniqueness) stay, just shorter. No code changes.

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

src/app.rs

@@ -479,14 +479,9 @@ fn AlternativeCard(
         }
     });
 
-    // File fields don't fit a live-typed RwSignal<String> - they get
-    // their own map of element refs, read (and uploaded) only at submit
-    // time, and are excluded from `field_map` below. `select` fields
-    // don't fit it either (a multi-select's value is a *set* of ids,
-    // not one string) - they get their own `Vec<String>`-signal map,
-    // plus a plain (non-reactive, content-derived) record of which
-    // select fields are `multiple`, read back at submit time to decide
-    // whether to emit a JSON array or a single string.
+    // Text fields live in field_map; file fields (element refs, read at
+    // submit) and select fields (a set of ids, plus which are multiple)
+    // each need their own shape.
     let mut field_map: std::collections::HashMap<String, RwSignal<String>> =
         std::collections::HashMap::new();
     let mut file_refs: std::collections::HashMap<String, NodeRef<leptos::html::Input>> =
@@ -511,10 +506,9 @@ fn AlternativeCard(
         }
     }
 
-    // Prefixes field DOM ids with the alternative too, not just the
-    // question - two alternatives on the same page (e.g. both asking for
-    // "email") would otherwise mint the same id twice, which is invalid
-    // HTML and makes <label for=…> pick the wrong input.
+    // DOM ids are prefixed with question AND alternative - two
+    // alternatives on one page can both ask for "email", and duplicate
+    // ids would make <label for=...> pick the wrong input.
     let field_prefix = format!(
         "{question_id}-{}",
         alternative.name.to_lowercase().replace(' ', "-")