binary http body: bodyBytes(), Buffer.from base64, serveFile, remove body size limit

[cs01]

Summary

• Binary HTTP body support: c.req.bodyBytes() returns a Uint8Array of the raw request body, enabling binary upload handling (images, files, etc.)
• Uint8Array.fromRawBytes(str, len): new built-in that wraps a raw C string + length into a Uint8Array without null-termination assumptions
• Buffer.from(str, 'base64'): new base64 decode built-in backed by base64-bridge.c, returns a Uint8Array
• bytesResponse(data, status, headers): new codegen primitive that constructs a binary HttpResponse from a Uint8Array
• c.bytes(data, contentType): new Context method for returning binary responses (implemented in ChadScript on top of bytesResponse)
• serveFile(path, contentType): serve a file from disk; imported from chadscript/http, implemented in ChadScript on top of fs.readFileSync + bytesResponse
• Remove 1 MB body cap: lws-bridge now mallocs exactly Content-Length bytes; large bodies (multi-MB uploads) now receive fully
• Fix chunked read buffer: reset data_len after each chunk so subsequent TCP segments are placed at offset 0 — fixes truncated large-body reads
• Fix body_len type: changed from int64_t to double in the bridge request struct so ChadScript reads it correctly as a number
• Fix router method matching: same-path routes with different HTTP methods now match the correct handler
• Fix closure analyzer: method_call, call, and await statement node types were missing from the closure mutation checker, causing false negatives
• CI: base64-bridge.o and time-bridge.o are now both included in release artifact packaging and vendor verification

Test plan

• POST a request with a body > 1 MB and verify it arrives complete via c.req.bodyBytes()
• Upload a PNG/binary file and round-trip it through bodyBytes() → Buffer.from(..., 'base64') → decode
• serveFile() serves a static binary file with correct Content-Type
• c.bytes() returns a binary response with correct headers and body length
• Routes GET /foo and POST /foo both match their respective handlers
• npm run verify passes (all unit tests + self-hosting)