config, mcp, gui: specs from sources, spec-blind suites, and the bugs they found

ledger-config: parse gets a sourced spec. A fiscal year starts on the
first of a month (IRS Pub. 538); tax_classification is read by whole
words (Treas. Reg. 301.7701-3, Schedule C instructions; "business corp"
no longer reads as an S corp, "corporation or S corporation" is refused);
duplicate or blank members and shared capital accounts are refused; a
negative or non-grammatical receipt threshold is refused; codes trimmed.
tests/spec_config.rs (65 spec-blind tests, 14 properties), fuzz target
fuzz_config_parse (weekly). Mutation: 55 of 55 viable caught (from 25/38).

The receipt policy moves to ledger-config, with one loader
(effective_receipt_policy) and one decimal grammar, so the server and
the viewer enforce and show the same rule (the viewer had its own: only
expense-like debits, a silent $25 default, and no config.json).

ledger-mcp: a module spec (MCP 2025-06-18 tools, JSON-RPC 2.0, the
operating contract). Amounts in are exactly -?digits[.digits]; a number
that is one account's code and another's id (vendors, classes alike) is
refused, not guessed; the threshold is validated at startup. Fixed:
add_line with a bad class journaled the line before refusing;
profit_and_loss_by_class ignored `class`; aging buckets said "0". A wire
in front of rmcp answers malformed JSON with -32700 and invalid requests
with -32600 and their id (rmcp dropped the first, omitted the id).
tests/spec_mcp.rs (26 spec-blind tests: every tool's result against its
own outputSchema, a random-call state machine checking the journal is
untouched by every refusal, amount grammar, previews, the receipt policy).

ledger-gui: money, accounting, and dollars never round (they rounded to
cents, banker's style); export file names avoid Windows device names,
trailing dots and spaces, empty names, and 255-byte overflow; specs on
attention, history, fuzzy search, and axis ticks.

ledger-core: the lifetime profit_and_loss is renamed unclosed_earnings
(docs/testing.md #3).

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

fuzz/Cargo.lock

@@ -1413,6 +1413,17 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "ledger-config"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "ledger-core",
+ "rust_decimal",
+ "serde",
+ "toml 1.1.8+spec-1.1.0",
+]
+
 [[package]]
 name = "ledger-core"
 version = "0.1.0"
@@ -1430,6 +1441,7 @@ version = "0.0.0"
 dependencies = [
  "arbitrary",
  "chrono",
+ "ledger-config",
  "ledger-core",
  "ledger-import",
  "ledger-store",
@@ -2337,6 +2349,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_spanned"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4e7523beb55eece201a2356bee0bbca0d1ab466c14c07703b2e0ee6d42cb0c2c"
+dependencies = [
+ "serde_core",
+]
+
 [[package]]
 name = "serde_yaml"
 version = "0.9.34+deprecated"
@@ -2656,11 +2677,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc1beb996b9d83529a9e75c17a1686767d148d70663143c7854d8b4a09ced362"
 dependencies = [
  "serde",
- "serde_spanned",
+ "serde_spanned 0.6.9",
  "toml_datetime 0.6.11",
  "toml_edit 0.22.27",
 ]
 
+[[package]]
+name = "toml"
+version = "1.1.8+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20489e00e4d8741d6be680764cc12e270655e375a20d1011e844a9c3379e678d"
+dependencies = [
+ "indexmap",
+ "serde_core",
+ "serde_spanned 1.1.2",
+ "toml_datetime 1.1.2+spec-1.1.0",
+ "toml_parser",
+ "toml_writer",
+ "winnow 1.0.4",
+]
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.11"
@@ -2687,7 +2723,7 @@ checksum = "41fe8c660ae4257887cf66394862d21dbca4a6ddd26f04a3560410406a2f819a"
 dependencies = [
  "indexmap",
  "serde",
- "serde_spanned",
+ "serde_spanned 0.6.9",
  "toml_datetime 0.6.11",
  "toml_write",
  "winnow 0.7.15",
@@ -2720,6 +2756,12 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
 
+[[package]]
+name = "toml_writer"
+version = "1.1.3+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06bdbd8cfc056b8d2e2e85f29b56a3bdbecb527cef81eb39e3e7b98af4652770"
+
 [[package]]
 name = "ttf-parser"
 version = "0.25.1"
@@ -2807,7 +2849,7 @@ dependencies = [
  "indexmap",
  "rustc-hash",
  "stacker",
- "toml",
+ "toml 0.8.23",
  "typst-library",
  "typst-macros",
  "typst-syntax",
@@ -2923,7 +2965,7 @@ dependencies = [
  "smallvec",
  "syntect",
  "time",
- "toml",
+ "toml 0.8.23",
  "ttf-parser",
  "two-face",
  "typed-arena",
@@ -3038,7 +3080,7 @@ dependencies = [
  "ecow",
  "rustc-hash",
  "serde",
- "toml",
+ "toml 0.8.23",
  "typst-timing",
  "typst-utils",
  "unicode-ident",