Server comments describe the code to a stranger (#6221)

Rule 32 "Comments describe the product to a stranger" sweep over
src/, alembic/ and tests/. Comments and docstrings now say what the code
does and the reason as a present-tense constraint, briefly.

Removed:
- issue, task, note, rule, milestone and family-idea references
- "used to" / before-and-after narration
- quotes of decisions and incident stories from the deploying instance
- paragraph-length arguments, where a line or two carries the fact

Kept every hazard as a present-tense fact, e.g. timing oracles, the
proxy hop direction, and migrations that must stay frozen.

Also:
- Three test names lose "still"/"used to"/"pre_m304" phrasing.
- pyproject's description drops "FabledSword family".

The history these comments carried stays in Scribe and in git log.
A comment-stripping diff (Scribe snippet #6226 "codeonly.py — prove a
diff changed only comments") shows no code changed apart from the
renamed tests and the description string.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_settings.py

@@ -21,7 +21,7 @@ def test_validate_coerces_bool_and_int():
 
 def test_each_integer_with_a_dangerous_range_is_bounded():
     """Session length 0 expired every session at once; an attachment limit above the
-    body ceiling allowed files no request could carry; a negative one refused all (#5384)."""
+    body ceiling allowed files no request could carry; a negative one refused all."""
     for key, bad, good in (
         ("session_ttl_days", 0, 1),
         ("trash_retention_days", -1, 0),