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-config/src/lib.rs

@@ -108,6 +108,58 @@ pub struct BooksSettings {
     /// statement treats as investing (loans the company makes, investments
     /// it buys: ASC 230-10-20). Registered fixed assets need not be listed.
     pub investing_accounts: Vec<String>,
+    /// `[books] asset_tag_prefix`: the prefix of generated asset tags
+    /// ("FL" for "FL-0001"). Unset: [`BooksSettings::asset_tag_prefix`]
+    /// derives it from the company name.
+    pub asset_tag_prefix: Option<String>,
+}
+
+impl BooksSettings {
+    /// The prefix generated asset tags use: `[books] asset_tag_prefix`, or
+    /// else the initials of the company name's words, legal-form words
+    /// (LLC, Inc, Corp, ...) left out, at most 8 ("Fernhill Labs LLC" →
+    /// "FL"); "FA" (fixed asset) when the name gives none.
+    pub fn asset_tag_prefix(&self) -> String {
+        if let Some(p) = &self.asset_tag_prefix {
+            return p.clone();
+        }
+        const FORMS: &[&str] = &[
+            "llc",
+            "l",
+            "c",
+            "inc",
+            "incorporated",
+            "corp",
+            "corporation",
+            "co",
+            "company",
+            "ltd",
+            "limited",
+            "llp",
+            "lp",
+            "pllc",
+            "pc",
+            "pa",
+            "the",
+            "and",
+            "of",
+        ];
+        let initials: String = self
+            .company
+            .name
+            .split(|c: char| !c.is_ascii_alphanumeric())
+            .filter(|w| !w.is_empty() && !FORMS.contains(&w.to_ascii_lowercase().as_str()))
+            .filter_map(|w| w.chars().next())
+            .filter(char::is_ascii_alphabetic)
+            .map(|c| c.to_ascii_uppercase())
+            .take(8)
+            .collect();
+        if initials.is_empty() || self.company.name == Company::default().name {
+            "FA".to_string()
+        } else {
+            initials
+        }
+    }
 }
 
 #[derive(Deserialize)]
@@ -149,6 +201,7 @@ struct BooksSection {
     financing_accounts: Vec<String>,
     #[serde(default)]
     investing_accounts: Vec<String>,
+    asset_tag_prefix: Option<String>,
 }
 
 /// The return a federal tax classification files (docs/spec/sources/
@@ -444,6 +497,21 @@ pub fn parse(text: &str) -> Result<BooksSettings, String> {
         cash_accounts: codes("cash_accounts", raw.books.cash_accounts)?,
         financing_accounts: codes("financing_accounts", raw.books.financing_accounts)?,
         investing_accounts: codes("investing_accounts", raw.books.investing_accounts)?,
+        asset_tag_prefix: match raw.books.asset_tag_prefix {
+            Some(p)
+                if !p.is_empty()
+                    && p.len() <= 8
+                    && p.chars().all(|c| c.is_ascii_alphanumeric()) =>
+            {
+                Some(p)
+            }
+            Some(p) => {
+                return Err(format!(
+                    "[books] asset_tag_prefix {p:?}: 1 to 8 letters or digits"
+                ));
+            }
+            None => None,
+        },
     })
 }