feat: add config toggle to disable secret redaction

New config option:

  security:
    redact_secrets: false  # default: true

When set to false, API keys, tokens, and passwords are shown in
full in read_file, search_files, and terminal output. Useful for
debugging auth issues where you need to verify the actual key value.

Bridged to both CLI and gateway via HERMES_REDACT_SECRETS env var.
The check is in redact_sensitive_text() itself, so all call sites
(terminal, file tools, log formatter) respect it.

agent/redact.py

@@ -8,6 +8,7 @@ the first 6 and last 4 characters for debuggability.
 """
 
 import logging
+import os
 import re
 from typing import Optional
 
@@ -73,9 +74,12 @@ def redact_sensitive_text(text: str) -> str:
     """Apply all redaction patterns to a block of text.
 
     Safe to call on any string -- non-matching text passes through unchanged.
+    Disabled when security.redact_secrets is false in config.yaml.
     """
     if not text:
         return text
+    if os.getenv("HERMES_REDACT_SECRETS", "").lower() in ("0", "false", "no", "off"):
+        return text
 
     # Known prefixes (sk-, ghp_, etc.)
     text = _PREFIX_RE.sub(lambda m: _mask_token(m.group(1)), text)