feat(lang,stdlib): 64-bit long type + 64-bit Hash variants (issue #17)

Add `long`, a 64-bit signed integer primitive (i64), threaded through
codegen: llty; int<->long coercion (coerce_code/to_long) at let/assign/
return/call-args; i64 arithmetic + comparison promotion in emit_bin;
unary negate/~; print via %lld and str()/interpolation via @fn_long_str.
Editor vocabulary (syntax header, TextMate grammar, formatter, LSP)
synced; check-vocabulary green. Numeric literals stay i32 — build large
values by widening (documented on the type page).

Complete the Hash.* namespace (issue #17) with both 32- and 64-bit
algorithms: Hash.of/fnv1a/crc32/mix/combine (32-bit) and
Hash.of64/fnv1a_64/mix64 (64-bit, returning long). Deterministic and
C-free; CRC-32 (poly 0xEDB88320) and FNV vectors verified against
reference implementations.

Tests: selfhost/tests/{hash,long}.ludic. Docs: docs/language/hash/*,
type-long.md. Seed reseeded; C-free bootstrap fixpoint holds; 23
selfhost + 45 regression + 29 tooling checks green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/language/hash/_section.md

@@ -0,0 +1,9 @@
+---
+id: hash
+title: Hash
+order: 6
+---
+
+Fast, non-cryptographic hashing for everyday game needs: turning string IDs into integer handles, mixing a few numbers into one deterministic seed, and checksumming data to catch corruption. Every function is plain 32-bit integer arithmetic with a defined byte order and fixed constants, so a given input hashes to exactly the same value on every platform and every run — the guarantee that makes it safe for procedural generation and lockstep networking. Results are 32-bit and print as signed integers. Arguments are positional.
+
+Not for security. These hashes are fast and reversible — never use them for passwords, tokens, or tamper-proofing. For secure hashing reach for the cryptography library instead.