P3: rename accounts, one set of period defaults, tax categories warn or refuse (defects 15, 16, 8)

books.rename_account; account names trimmed, bounded, refused when a
sibling's or TIN-shaped; books.show refuses what its target ignores. A
report asked for without dates covers this fiscal year so far, everywhere
(one rule for tools, descriptions and the viewer; the IIF and CPA package
keep their own dates). policy.require_tax_category warns or refuses; a
Form 4797 gain is shown apart on every return.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-gui/src/pages/profit.rs

@@ -281,7 +281,8 @@ fn spending_changes(ui: &mut Ui, b: &Books, shell: &mut Shell<'_>) {
         },
     );
     if let Some(id) = go {
-        shell.state.accounts.range = Some((ms - Months::new(3), b.today));
+        shell.state.accounts.range =
+            crate::pages::accounts::RegisterRange::Dates(ms - Months::new(3), b.today);
         shell.go(Route::Account(id));
     }
     ui.add_space(16.0);