New five-class consent model for Artifact permissions (experimental)

What

• A new consent model for the Artifact tool, called "five-class asks," is being built behind the CLAUDE_CODE_ARTIFACT_FIVE_CLASS_ASKS environment variable (off by default), which latches the behavior on or off for the life of the process and reports whether it was on via telemetry.
• When enabled, it changes how Claude asks for permission on artifact actions:
  • Pinning someone else's artifact to your own list is now auto-allowed instead of prompting.
  • Uploading, reading (list_assets/read_asset/list_files/read_file), commenting, and replying all go through a new classification system (pathAsk, readRule, flaggedSpelling, outsideAsk, hardLinked, plus an unknown/someone_else/from_type/cowritten split) and a new ruling flow, instead of always asking.
  • Uploads get an "already approved this session" fast path.
  • Reading someone else's shared artifact can be auto-allowed via a per-conversation "class consent" latch, with the message "Reading ... needs no approval"; wording also changed from "another person's artifact" to "someone else's artifact."
• When the experiment is off, the previous single-path deny/ask logic is used unchanged.

Why

This reduces how often Claude has to interrupt with a permission prompt for routine, low-risk artifact actions, like pinning or re-reading something already approved, while still asking for genuinely new or risky ones.