Cleaned up the protocol layer and metadata

- request() now reads exactly the expected response length with
  read_exact instead of a single non-guaranteed fill_buf, fixing a
  latent bug where a response split across multiple TCP packets could
  be mistaken for malformed data; the per-method length checks are now
  redundant and were removed
- sequence_number wraps explicitly via wrapping_add instead of
  relying on implicit (and debug-vs-release inconsistent) overflow
  behavior after 65536 requests
- get_name validates UTF-8 strictly instead of silently lossy-decoding
  invalid bytes; on invalid data it now returns the FromUtf8Error
  itself (byte-level \0 trimming moved after the UTF-8 check), letting
  the caller choose to fail or fall back to a lossy rendering
- removed the unused Default derive from Clock and Record
- removed npm from the CI image (no JS/Node in this repo), fixed a
  typo in a CI step name
- fixed the Cargo.toml license field to the actual SPDX identifier
  (AGPL-3.0-or-later, per the notice at the end of LICENSE) instead of
  the free-text "GNU AGPLv3.0"

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Cargo.toml

@@ -2,7 +2,7 @@
 name = "r701"
 version = "0.1.0"
 edition = "2021"
-license = "GNU AGPLv3.0"
+license = "AGPL-3.0-or-later"
 repository = "https://git.nicolabelluti.me/nicolabelluti/r701"
 
 [dependencies]