add url and urlsearchparams classes with c bridge

[cs01]

feat: add URL and URLSearchParams classes

Adds URL and URLSearchParams as built-in classes, implemented via a new C bridge (url-bridge.c). Also fixes two CI bugs discovered during development: missing bridge artifacts in the cross-compile SDK tarball, and stage1 compiling with native CPU instructions that crash GitHub's x86-64 runners.

What's new

URL

const u = new URL("https://example.com:8080/path?q=hello#section");
u.protocol  // "https:"
u.hostname  // "example.com"
u.port      // "8080"
u.host      // "example.com:8080"
u.pathname  // "/path"
u.search    // "?q=hello"
u.hash      // "#section"
u.origin    // "https://example.com:8080"
u.href      // full URL string

URLSearchParams

const p = new URLSearchParams("q=hello&page=2");
p.get("q")           // "hello"
p.has("page")        // true
p.set("q", "world")
p.append("tag", "foo")
p.delete("page")
p.toString()         // "q=world&tag=foo"

Implementation

• c_bridges/url-bridge.c (new) — GC-aware C bridge. URL parsing: cs_url_parse_protocol, cs_url_parse_hostname, cs_url_parse_port, cs_url_parse_pathname, cs_url_parse_search, cs_url_parse_hash. URLSearchParams: cs_urlsearch_get, cs_urlsearch_has, cs_urlsearch_set, cs_urlsearch_append, cs_urlsearch_delete, cs_urlsearch_tostring.
• src/codegen/stdlib/url.ts (new) — codegen for URL and URLSearchParams constructor and method dispatch.
• src/codegen/infrastructure/symbol-table.ts — defineUrl/defineUrlSearchParams now initialize all 17 Symbol fields. Previously only 5 were set; getConcreteClass reads symbol.concreteClass at index 15, causing a SIGSEGV from reading past the end of the struct.
• scripts/build-vendor.sh, src/compiler.ts, src/native-compiler-lib.ts — build and link url-bridge.o.

CI fixes

• scripts/build-target-sdk.sh — add url-bridge.o to the cross-compile SDK tarball. Missing bridges cause linker failures when cross-compiling macOS → Linux.
• .github/workflows/ci.yml — add url-bridge.o to all 4 artifact copy locations (Linux verify, Linux release, macOS verify, macOS release).
• tests/self-hosting.test.ts — pass --target-cpu=x86-64 to both stage0 and stage1 builds. Stage1 is compiled by stage0 and inherits the same CPU target issue; without the flag it emits AVX/newer instructions that SIGILL on GitHub's baseline x86-64 runners.

Commits

fd484b3 fix: pass --target-cpu=x86-64 to stage1 compilation
a4db449 fix: add url-bridge.o to cross-compile target sdk packaging
8856094 fix: add url-bridge.o to ci install/release
64f4a6c add url and urlsearchparams classes with c bridge

18 files changed, 659 insertions(+), 11 deletions(-)