Fixed assets, fully featured: tags, serials, acquisition links, label sheets, the fixed asset register, and an Assets section in the viewer; fix a flaky verify

- core: asset tags (generated PREFIX-0001 or the human's own; unique ignoring case; never reused by another asset) and serial numbers (rules.md B-24); a journaled link from an asset to the entry that acquired it (posted, unreversed, debiting the cost account); fixed_asset_register(as_of), reconciled to the GL (unposted depreciation, unregistered cost)
- store: asset.tagged, asset.serial_set, asset.acquisition_linked journaled, replayed, projected (schema v9); differs_from now also compares control roles and tag history
- config: [books] asset_tag_prefix, default the company's initials without legal-form words
- import: Avery 5160/8160 label sheets with QR codes (geometry vendored from Avery, docs/spec/sources/avery-5160.md); the register as XLSX and PDF
- mcp: register_asset tags (and links) automatically; books.label_asset, books.asset_labels; asset tools take a tag; books.show asset / assets page / register report; export fixed_asset_register (json, csv, xlsx, pdf) and in the CPA package
- viewer: Assets page (register, reconciliation), asset page (identity, schedule posted vs not, entries, documents), Fixed asset register report, global search by tag/serial/description, journal text, needs-attention items
- fix: verify compared snapshot amounts as strings; a zero total summed in hash-map order could print "0" or "0.00", so agreeing books failed verify at random. Now by value (regression test)
- tests: spec-blind suites for tags, register, prefix, store, MCP; label and register PDF/XLSX tests; viewer tests

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX

crates/ledger-gui/tests/screens.rs

@@ -45,6 +45,12 @@ fn screenshots() {
     let first_cash = loaded.cash_accounts.first().copied().unwrap_or(1);
     let last_doc = loaded.attachments.last().map(|a| a.id).unwrap_or(1);
     let last_event = loaded.seq();
+    let first_asset = loaded
+        .ledger
+        .registered_assets()
+        .next()
+        .map(|a| a.id)
+        .unwrap_or(1);
     drop(loaded);
     let routes: Vec<(&str, Route)> = vec![
         ("overview", Route::Overview),
@@ -68,8 +74,14 @@ fn screenshots() {
         ("tax", Route::Reports(ReportKind::TaxSummary)),
         ("v1099", Route::Reports(ReportKind::Vendor1099)),
         ("ar", Route::Reports(ReportKind::ArAging)),
+        (
+            "asset-register",
+            Route::Reports(ReportKind::FixedAssetRegister),
+        ),
         ("accounts", Route::Accounts),
         ("account", Route::Account(first_cash)),
+        ("assets", Route::Assets),
+        ("asset", Route::Asset(first_asset)),
         ("document", Route::Document(last_doc)),
         ("event", Route::JournalEvent(last_event)),
         ("documents", Route::Documents),