`constants.py` entries lack `tag`, `status`, and `description` metadata from upstream CSV

[sumanjeet0012]

Each entry in constants.py currently stores only the codec prefix code. The upstream multicodec table.csv has 5 columns (name, tag, code, status, description), but tools/update-table.py discards tag, status, and description during generation.

Problem

Current format in constants.py:

CODECS = {
    "sha2-256": {"prefix": 0x12},
    "dag-pb":   {"prefix": 0x70},
    "ip4":      {"prefix": 0x04},
}

The upstream CSV contains significantly more information per codec:

name	tag	code	status	description
sha2-256	multihash	0x12	permanent
dag-pb	ipld	0x70	permanent
ip4	multiaddr	0x04	permanent
shake-128	multihash	0x18	draft

This metadata is discarded by tools/update-table.py (line 82), which only writes the prefix:

# tools/update-table.py, line 82:
value = "{'prefix': {code}, },".format(code=codec["code"])

Proposed Solution

1. Modify tools/update-table.py to include tag, status, and description in the output:

   "sha2-256": {"prefix": 0x12, "tag": "multihash", "status": "permanent", "description": ""},

2. Regenerate constants.py using the updated script.

3. Add Code.status and Code.description properties in code.py that read from the enriched CODECS dict.

4. Update NAME_TABLE and CODE_TABLE derivations to remain backward-compatible (they only need name↔prefix mapping).

5. Add tests verifying that every codec has tag, status fields populated.

Related

• Generator script: tools/update-table.py
• Go equivalent: go-multicodec includes status ("permanent"/"draft") and description in generated code comments