build, deploy, inbound, dmarc, backup, e2e: cite the source of what they rely on (assumptions part C)

Comments only, no behaviour changed. Each main.cf/master.cf parameter the
build sets, the wrapper's and the reload hook's reliance on Postfix 3.7.11
(postfix-script, master.5, postconf.5, cleanup_init.c, smtpd_peer.c,
README_FILES), supervisor 4.2.5 (process.py, options.py, events.rst),
logrotate 3.21.0, OpenDKIM's config, Cyrus SASL's sasldb, rspamd 3.11.1
(milter_headers.lua, multimap, the map watcher), Docker Compose, CoreDNS
and certbot now say where that is written. Measurements already there stay
measurements ("date not recorded" where none was); hand-composed fixtures
say so.

Contradictions left for their own commits: C-P31 cleanup's size limit,
C-P42 master outside supervisor's signal, C-V5/V6 startsecs, C-V10,
C-S3/Q3 sasldb written in place, C-Q4/A1 certbot's symlinks, C-R7 rspamd
skips local clients but the signature routine does not, C-P8, C-R4, C-R12,
C-M7, C-E2, C-K8/K9, C-D1.

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

deploy/antispam/rspamd/multimap.conf

@@ -3,6 +3,11 @@
 # The allow and deny lists kept in the panel (Inbound > Filter lists). SelfPost
 # writes them as six files under data/antispam/, which the fragment mounts at
 # /etc/rspamd/selfpost; rspamd rereads a file when it changes, no restart.
+# (rspamd 3.11.1, src/libserver/maps/map.c: a file map is watched with libev's
+# ev_stat - inotify where the kernel has it, else a stat poll every
+# map_watch_interval x map_file_watch_multiplier, 5min x 0.1, conf/options.inc;
+# docs.rspamd.com/configuration/maps asks for an atomic rename, which
+# internal/inbound writes with.)
 #
 # Deny wins over allow, whichever entries match. A denied sender is refused
 # before anything else is looked at (a prefilter). An allowed one is not
@@ -10,7 +15,17 @@
 # first decide - but given a weight no spam score outweighs, which a refusal
 # by the deny list still overrides.
 #
-# A domain entry is that domain, not its subdomains.
+# A domain entry is that domain, not its subdomains. (rspamd 3.11.1,
+# src/libserver/maps/map_helpers.c: a hash map is looked up by the whole key,
+# case-insensitively - rspamd_icase_hash, rspamd_lc_cmp; "email:domain" gives
+# the address's domain part, src/plugins/lua/multimap.lua, apply_addr_filter().)
+#
+# A refusal is rspamd's "pre-result": multimap.lua calls task:set_pre_result()
+# with the rule's action and message, and that action stands whatever the score
+# (docs.rspamd.com/modules/multimap, "action"). The message reaches the client
+# as "554 5.7.1 <message>": src/libserver/protocol.c, rspamd_scan_result_ucl(),
+# puts it into messages.smtp_message, src/libserver/milter.c,
+# rspamd_milter_send_task_results(), replies with it.
 #
 # SelfPost counts how often an entry decided a message by what these rules
 # leave behind: the deny message below and the names of the allow symbols.