chameleon 2.31.0

Ruby cross-file blast radius, plus per-language gaps closed by a proactive
cross-matrix verification of every recent fix.

Added

• Ruby constant-reference reverse index (cross-file blast radius). Ruby has
  no static named-export surface (require pulls a whole file by side effect),
  so it never got the TS/Python reverse index — the biggest cross-file blind
  spot on a Rails monolith. The new index inverts Ruby's class/constant graph:
  for each constant, the files that define it and the files that reference it
  (via a constant-receiver call site), built from parse data already collected.
  query_symbol_importers now returns the Ruby blast radius (editing the file
  that defines a widely-used service class lists its callers), and the autopass
  blast-radius gate consumes it. The index is built for Ruby at bootstrap/refresh
  and hashed into the trust SHA. Existing Ruby repos pick it up on their next
  /chameleon-refresh.
• Ruby constant-existence break for PR review. get_crossfile_context and
  the turn-end advisory now flag a class/module that the index records as defined
  in an edited file but the file no longer defines, while other files still
  reference it — the Ruby analogue of a removed export still imported.
  High-confidence only (one defining file, bare top-level name, a referencer that
  still names it).
• /chameleon-teach accepts an optional archetype to scope a free-form
  idiom (so it surfaces first on that archetype's edits); omitted, the idiom
  stays general and applies to every archetype.

Fixed

• Autopass blast-radius now covers Ruby (it keyed on the reverse-index
  extensions and read 0 for .rb, inconsistent with the Stop judge-router that
  already counted Ruby fan-out).
• Paren-less Kernel#eval is now detected (eval "..." / eval s /
  eval %(...)) — the rule only matched eval(, so the idiomatic Ruby form
  slipped enforcement entirely. Fires at error severity, no false positives on
  instance_eval/class_eval, member calls, assignments, or comment/string
  mentions.
• Lint wording is language-correct for Python and Ruby. The node-kind
  humanizer had no Python (libcst) labels, so ClassDef/FunctionDef leaked
  raw; and the lint_file tool never passed the language through, so Ruby and
  Python output used the TypeScript "default export" framing. Both fixed.
• The inline-override hint offers # chameleon-ignore to Python (it only
  special-cased Ruby; Python developers got the // token, a syntax error in
  their file).
• Contract breaks now detect the canonical Ruby service-object. A class with
  both a class method and an instance method of the same name (def self.call +
  def call) was dropped as ambiguous, missing the very method that has callers;
  the singleton (the constant-receiver target) is now kept.