style: format the whole tree with cargo fmt (stock defaults, #35)

One-time, mechanical reformat — no functional changes. The tree was not
rustfmt-clean (~1800 hunks across ~100 files); this brings it to stock
`cargo fmt` defaults so a `cargo fmt --check` CI gate can follow.
Behaviour-preserving: 2509 pass / 0 fail / 1 ignored (unchanged baseline),
clippy clean. A .git-blame-ignore-revs entry follows so `git blame`
skips this commit.

src/dsl/command.rs

@@ -549,9 +549,7 @@ pub enum AppCommand {
     /// word like `insert` / `create` / `show`, or `types`), the
     /// focused detail for that command (or command group sharing
     /// the entry word).
-    Help {
-        topic: Option<String>,
-    },
+    Help { topic: Option<String> },
     /// Show a contextual tier-3 hint (H2 / ADR-0053). No argument:
     /// when submitted, it expands on the most recent runtime error
     /// (the buffer is empty post-submit). The live-input surface is
@@ -580,7 +578,10 @@ pub enum AppCommand {
     /// Unpack a zip into a new project and switch to it.
     /// `target` overrides the project name (default: taken from
     /// the zip).
-    Import { path: String, target: Option<String> },
+    Import {
+        path: String,
+        target: Option<String>,
+    },
     /// Switch the persistent input mode.
     Mode { value: ModeValue },
     /// Show or set the messages verbosity.
@@ -791,9 +792,7 @@ impl PartialEq for Operand {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {
             (Self::Column { name: a, .. }, Self::Column { name: b, .. }) => a == b,
-            (Self::Literal { value: a, .. }, Self::Literal { value: b, .. }) => {
-                a == b
-            }
+            (Self::Literal { value: a, .. }, Self::Literal { value: b, .. }) => a == b,
             _ => false,
         }
     }
@@ -817,7 +816,9 @@ pub enum CompareOp {
 /// a single row in the metadata table.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum RelationshipSelector {
-    Named { name: String },
+    Named {
+        name: String,
+    },
     Endpoints {
         parent_table: String,
         parent_column: String,
@@ -1156,9 +1157,7 @@ impl Command {
                     parent_column,
                     child_table,
                     child_column,
-                } => format!(
-                    "from {parent_table}.{parent_column} to {child_table}.{child_column}"
-                ),
+                } => format!("from {parent_table}.{parent_column} to {child_table}.{child_column}"),
             },
             // A constraint command's subject is the dotted
             // `<table>.<column>` it acts on (ADR-0029 §2.2).