fix(evolution): encode a JS boolean Bool constant as its own value (#398)

[Kshot3000]

Fixes #398.

The bug

ConstantValue permits a plain JS boolean for a Bool constant, but the flat encoder's Bool branch read .index off the value:

const boolVal = value as { index: bigint }
pushBit(state, boolVal.index === 0n ? 0 : 1)

A JS boolean has no .index, so undefined === 0n is false and false was encoded with the True bit. con bool false and con bool true produced identical flat bytes (0100004a21 for a bare constant program), so a script built from a false boolean computed that constant as true.

The fix

The Bool branch of encodeData now handles the primitive form the type advertises, as the issue suggests:

const bit = typeof value === "boolean" ? (value ? 1 : 0) : (value as { index: bigint }).index === 0n ? 0 : 1
pushBit(state, bit)

The decoded { index } form encodes exactly as before, and because the list/pair branches route through the same encodeData, JS booleans nested in a list Bool are fixed by the same change.

Tests

Four new tests in test/UPLC.test.ts, all written against main first:

• JS false encodes differently from JS true and decodes back to { index: 0n } — on main both encoded to 0100004a21 (RED)
• JS true decodes back to { index: 1n } (control, passed before and after)
• JS booleans match the { index } representation byte for byte — on main JS false gave 0100004a21 against the { index: 0n } form's 0100004a01 (RED)
• JS booleans nested in a list of Bool roundtrip with the right indices (RED on main)

With the fix: UPLC test file 43/43, full package suite 1682 passed / 75 skipped / 0 failed (test files 101 passed / 1 skipped of 102; main baseline 1678 + the 4 new tests), tsc --noEmit and eslint clean. A patch changeset is included.

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