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-mcp/tests/spec_mcp.rs

@@ -778,15 +778,29 @@ fn happy_path(name: &str) -> Mcp {
     m.ok("books.ap_aging", json!({"as_of": "2026-06-30"}));
 
     // Fixed assets.
-    let asset = m.ok(
+    let registered = m.ok(
         "books.register_asset",
         json!({"description": "Laptop", "purchase_date": "2026-01-10", "cost": "3000.00",
                "salvage_value": "0.00", "useful_life_months": 36, "cost_account": "1500",
                "accum_depr_account": "1510", "expense_account": "6500"}),
-    )["asset_id"]
-        .as_u64()
-        .unwrap();
+    );
+    assert_eq!(registered["tag"], "S-0001", "\"Spec Co\" without \"Co\": S");
+    let asset = registered["asset_id"].as_u64().unwrap();
     m.ok("books.asset_schedule", json!({"asset_id": asset}));
+    m.ok("books.asset_schedule", json!({"tag": "s-0001"}));
+    m.ok(
+        "books.label_asset",
+        json!({"asset": "S-0001", "tag": "LAPTOP-1", "serial": "SN 123"}),
+    );
+    m.ok("books.asset_labels", json!({}));
+    m.ok(
+        "books.asset_labels",
+        json!({"assets": ["LAPTOP-1"], "skip": 3}),
+    );
+    m.ok(
+        "books.export",
+        json!({"report": "fixed_asset_register", "format": "json", "as_of": "2026-03-31"}),
+    );
     m.ok("books.list_assets", json!({}));
     m.ok("books.run_depreciation", json!({"period": "2026-01"}));
     let dispose = json!({"asset_id": asset, "date": "2026-06-15", "proceeds": "1000.00",