chameleon 2.19.0

Security hardening from an internal source audit. chameleon treats the repo it
analyzes as untrusted input; this closes five places where that input was handled
less carefully than the rest of the code already handles it. No remote code
execution and no default-reachable exploit was found. The fixes raise the floor
and make these paths consistent with chameleon's own safe_open and
sanitize_for_chameleon_context discipline.

Security

• The turn-end correctness judge no longer puts edited-file contents on the
  process command line. The reviewer prompt embeds file diffs and was passed as
  a claude -p <prompt> argument, visible in ps aux / /proc/<pid>/cmdline to
  any local process for the spawn's lifetime. It is now fed on stdin. The judge
  also drops secret-bearing files (.env, .ssh, credential dotfiles) before it
  diffs them, so a secret a developer edits is never reconstructed into the
  prompt; this reuses the forbidden-segment set safe_open already enforces, now
  matched case-insensitively for case-insensitive filesystems.
• The archetype summary is sanitized before it reaches the model. Free prose
  from a committed archetypes.json flowed into the model-callable
  get_pattern_context response without sanitize_for_chameleon_context, while
  its sibling fields (idioms, witness) were sanitized. A crafted summary could
  carry a context-escape token or a forged status header; it now passes through
  the sanitizer like the rest.
• The per-edit "Nearby files" listing is sanitized. Raw sibling filenames
  were appended to the advisory <chameleon-context> block unsanitized, so a file
  named with a control token (for example <|im_start|>), a bidi override, or a
  forged [🦎 chameleon: ...] header could inject. The listing now goes through
  the same sanitizer as every other repo-derived field.
• The command log refuses symlinked paths. The exec-log directory and the
  per-session log file are created and opened without following symlinks (lstat
  before mkdir, O_NOFOLLOW on the leaf), closing a symlink TOCTOU on a shared
  TMPDIR where another local user could divert the log. The write fails open on
  any error rather than crash the recorder hook.
• The Ruby extractor runs from a neutral working directory with RUBYOPT and
  RUBYLIB scrubbed, matching the TypeScript extractor, so a poisoned interpreter
  option cannot make ruby load repo code before the parse-only prism_dump.rb
  runs.