docs/chore: Phase 1 doc/code hygiene (code-review.md § Phase 1)

Removes ~30 stale "Phase N" / historical-staging comment references from
code and shell scripts now that v1.0 is done; fixes a stale dashboard
comment claiming applications/send-log were unimplemented; adds a CSRF ADR
to security.md documenting the Origin-check-over-tokens decision; resolves
docs/logo in roadmap.md (directory doesn't exist, criterion already met);
adds a gofmt -l check to CI so unformatted Go fails the build.

The known-limitations write-up for the log-tailer offset gap (the other
Phase 1 item) was already present in architecture.md § Log tailer, so no
change was needed there.

gofmt/go vet/go test clean on both Go modules (main + test/e2e), verified
on the dev server.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

build/postfix-config.sh

@@ -106,7 +106,7 @@ postconf -e \
 	"smtpd_sender_restrictions=reject_sender_login_mismatch, permit"
 
 # Level-1 rate limit by client IP (spec 5 p.5). Backstop that keeps working even
-# if the journal-milter (level 2, Phase 8) is down.
+# if the journal-milter (level 2) is down.
 postconf -e \
 	"smtpd_client_message_rate_limit=${RATE_MSGS}" \
 	"anvil_rate_time_unit=${RATE_WINDOW}s"