Add deriveEq for Plinth similar to deriving stock Eq (#7433)

* feat(plutus-tx): add deriveEq Template Haskell function

Extract the Eq typeclass into PlutusTx.Eq.Class and add a new
PlutusTx.Eq.TH module providing deriveEq, a TH function that generates
PlutusTx.Eq instances analogous to GHC's `deriving stock Eq`.

This enables replacing hand-written structural equality instances with
a single `deriveEq ''TypeName` call, reducing boilerplate and ensuring
consistent pattern-matching with short-circuit evaluation and INLINABLE
pragmas across the codebase.

* test(plutus-tx): add unit and golden tests for deriveEq

Add comprehensive tests covering product types, sum types, newtypes,
records, void types, phantom types, and recursive types. Golden tests
capture exact TH-generated code to detect regressions.

Fix goldenCodeGen to use `pretty @String` for proper Doc type
conversion needed by nestedGoldenVsDoc.

* refactor(plutus-tx): replace manual Eq instances with deriveEq

Replace hand-written Eq instances for Rational and These with
deriveEq calls. The generated instances are structurally identical
to the manual ones.

* refactor(plutus-ledger-api): replace manual Eq instances with deriveEq

Replace hand-written PlutusTx.Eq instances across all V1, V2, and V3
modules (both Original and Data representations) with deriveEq calls.

MintValue retains its manual instance because its equality semantics
differ from structural equality (it normalizes zero-quantity entries).

* test: add golden tests for deriveEq generated code

Add golden TH tests capturing the exact generated Eq instances for
every type where manual instances were replaced with deriveEq. This
covers 42 types in plutus-ledger-api (V1/V2/V3, Original and Data
variants) and 2 types in plutus-tx (Rational, These).

These tests will detect any unintended changes to the generated
equality code.

* test: regenerate golden files affected by deriveEq

Variable naming in deriveEq-generated code differs from manual
instances, causing golden file updates in plutus-benchmark and
plutus-tx-plugin test suites.

* docs: add changelog entries for deriveEq feature

Add entries to plutus-tx and plutus-ledger-api changelogs documenting
the new deriveEq function and the migration from manual Eq instances.

* test: update AST size golden for Rational.compare after deriveEq changes

* test: make deriveEq golden tests deterministic for asData types

Strip TH-generated unique name suffixes (7+ digits) from golden test
output for Data-variant types (V*D.*), which use TH.newName via asData
and produce non-deterministic constructor names across compilations.

* test: regenerate golden files for cardano-constitution and plutus-benchmark

* fix: disable plutus-ledger-api-test on Windows (needs diff)

The golden tests added by deriveEq require the 'diff' binary which is
not available in the Windows (mingW64) cross-compilation environment.

* refactor: replace TH.pprint with custom width-aware pretty-printer

Replace formatTHOutput + TH.pprint with a new PlutusTx.Test.THPretty
module that uses prettyprinter's Wadler/Lindig algorithm with 100-column
page width. This produces much more readable golden test output -- lines
that previously stretched 200+ chars now wrap intelligently.

* style: remove commented-out deriveEq calls for AssocMap types

Replace commented-out deriveEq code with plain comments explaining
why PlutusTx.Eq instances are absent, addressing review feedback.

* style: add Haddock markers to MintValue Eq instance comments

---------

Co-authored-by: Yuriy Lazaryev <yuriy.lazaryev@iohk.io>

Author: bezirg

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/sorted.golden.cbor.size

@@ -1 +1 @@
-2045
+2042

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/sorted.golden.large.budget

@@ -1 +1 @@
-ExBudget {exBudgetCPU = ExCPU 406467137, exBudgetMemory = ExMemory 2070956}
+ExBudget {exBudgetCPU = ExCPU 406371137, exBudgetMemory = ExMemory 2070356}

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/sorted.golden.pir

@@ -247,37 +247,40 @@ program
                          Rational_match
                            ds
                            {bool}
-                           (\(n : integer) (d : integer) ->
+                           (\(l1l : integer) (l2l : integer) ->
                               Rational_match
                                 ds
                                 {bool}
-                                (\(n' : integer) (d' : integer) ->
+                                (\(r1r : integer) (r2r : integer) ->
                                    case
                                      (all dead. bool)
-                                     (equalsInteger n n')
+                                     (equalsInteger l1l r1r)
                                      [ (/\dead -> False)
-                                     , (/\dead -> equalsInteger d d') ]
+                                     , (/\dead -> equalsInteger l2l r2r) ]
                                      {all dead. dead})))
-                      (\(ds : Rational) (ds : Rational) ->
+                      (\(eta : Rational) (eta : Rational) ->
                          Rational_match
-                           ds
+                           eta
                            {Ordering}
-                           (\(n : integer) (d : integer) ->
+                           (\(ipv : integer) (ipv : integer) ->
                               Rational_match
-                                ds
+                                eta
                                 {Ordering}
-                                (\(n' : integer) (d' : integer) ->
-                                   let
-                                     !x : integer = multiplyInteger n d'
-                                     !y : integer = multiplyInteger n' d
-                                   in
+                                (\(ipv : integer) (ipv : integer) ->
                                    case
                                      (all dead. Ordering)
-                                     (equalsInteger x y)
+                                     (case
+                                        (all dead. bool)
+                                        (equalsInteger ipv ipv)
+                                        [ (/\dead -> False)
+                                        , (/\dead -> equalsInteger ipv ipv) ]
+                                        {all dead. dead})
                                      [ (/\dead ->
                                           case
                                             (all dead. Ordering)
-                                            (lessThanEqualsInteger x y)
+                                            (lessThanEqualsInteger
+                                               (multiplyInteger ipv ipv)
+                                               (multiplyInteger ipv ipv))
                                             [(/\dead -> GT), (/\dead -> LT)]
                                             {all dead. dead})
                                      , (/\dead -> EQ) ]

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/sorted.golden.small.budget

@@ -1 +1 @@
-ExBudget {exBudgetCPU = ExCPU 60269664, exBudgetMemory = ExMemory 276518}
+ExBudget {exBudgetCPU = ExCPU 60173664, exBudgetMemory = ExMemory 275918}

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/sorted.golden.uplc

@@ -1 +1 @@
-2036
+2044

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/unsorted.golden.cbor.size

@@ -1 +1 @@
-ExBudget {exBudgetCPU = ExCPU 568831992, exBudgetMemory = ExMemory 2943891}
+ExBudget {exBudgetCPU = ExCPU 568927992, exBudgetMemory = ExMemory 2944491}

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/unsorted.golden.large.budget

@@ -245,37 +245,40 @@ program
                          Rational_match
                            ds
                            {bool}
-                           (\(n : integer) (d : integer) ->
+                           (\(l1l : integer) (l2l : integer) ->
                               Rational_match
                                 ds
                                 {bool}
-                                (\(n' : integer) (d' : integer) ->
+                                (\(r1r : integer) (r2r : integer) ->
                                    case
                                      (all dead. bool)
-                                     (equalsInteger n n')
+                                     (equalsInteger l1l r1r)
                                      [ (/\dead -> False)
-                                     , (/\dead -> equalsInteger d d') ]
+                                     , (/\dead -> equalsInteger l2l r2r) ]
                                      {all dead. dead})))
-                      (\(ds : Rational) (ds : Rational) ->
+                      (\(eta : Rational) (eta : Rational) ->
                          Rational_match
-                           ds
+                           eta
                            {Ordering}
-                           (\(n : integer) (d : integer) ->
+                           (\(ipv : integer) (ipv : integer) ->
                               Rational_match
-                                ds
+                                eta
                                 {Ordering}
-                                (\(n' : integer) (d' : integer) ->
-                                   let
-                                     !x : integer = multiplyInteger n d'
-                                     !y : integer = multiplyInteger n' d
-                                   in
+                                (\(ipv : integer) (ipv : integer) ->
                                    case
                                      (all dead. Ordering)
-                                     (equalsInteger x y)
+                                     (case
+                                        (all dead. bool)
+                                        (equalsInteger ipv ipv)
+                                        [ (/\dead -> False)
+                                        , (/\dead -> equalsInteger ipv ipv) ]
+                                        {all dead. dead})
                                      [ (/\dead ->
                                           case
                                             (all dead. Ordering)
-                                            (lessThanEqualsInteger x y)
+                                            (lessThanEqualsInteger
+                                               (multiplyInteger ipv ipv)
+                                               (multiplyInteger ipv ipv))
                                             [(/\dead -> GT), (/\dead -> LT)]
                                             {all dead. dead})
                                      , (/\dead -> EQ) ]

cardano-constitution/test/Cardano/Constitution/Validator/Data/GoldenTests/unsorted.golden.pir

@@ -1 +1 @@
-ExBudget {exBudgetCPU = ExCPU 58587921, exBudgetMemory = ExMemory 267119}
+ExBudget {exBudgetCPU = ExCPU 58683921, exBudgetMemory = ExMemory 267719}