`path.join()` (zero args) throws TypeError instead of returning `.`

[proggeramlug]

Repro

import * as path from "node:path";
console.log("path.join():", path.join());

Actual (Perry)

TypeError: value is not a function
    at <anonymous>

(Process exits 0 — note: unhandled exception, exit code is also wrong; Node exits 1.)

Expected (Node)

path.join(): .

Impact

path.join() with zero arguments must return "." per the Node spec. It's the canonical "current directory" sentinel used by code like:

const args = process.argv.slice(2);
const target = path.join(...args);  // when args is empty, must yield "."

Today such code throws unhandled in Perry, terminating the program. The error message "value is not a function" suggests the implementation is doing something like arguments.reduce(joinFn) and calling joinFn on undefined when the args array is empty (reduce with no initial value on an empty array throws). The fix is to either provide an initial value or to detect zero-args up front and return ".".

Surfaced by test-files/test_parity_path.ts — the test runs through 20 successful path.basename/dirname/extname/join lines, then dies at this line, masking 21 downstream APIs (path.matchesGlob, path.normalize, path.parse, path.relative, path.resolve, path.toNamespacedPath, all of path.posix.* / path.win32.*, plus path.delimiter / path.sep).

Acceptance

The 2-line repro prints path.join(): . matching Node, AND Perry exits 1 (not 0) for unhandled exceptions in general (separate concern but visible here).

Related

Surfaced by test-files/test_parity_path.ts (committed in d0e84724). Was previously a smaller bug — yesterday Perry returned undefined for path.join() no-args; today it actively throws. Slight regression in error shape, same underlying gap.

[proggeramlug]

Fixed in v0.5.834 (commit 1cc5882 on main). path.join() returns ., path.join(single) returns the arg normalized. Issue's repro now prints byte-identical to Node.