docs: give the twelve experiments that had no architecture diagram one

An audit against the standard the series set — concepts, procedure,
commands, architecture diagram, evidence table, terminal output — found the
three new experiments met it while twelve of the original ones had no
diagram at all: A-0, A-1, A-3, A-4, A-5, A-6, A-8, B-0, B-2, B-7, C-2, D-2.

Each now has one drawn from what that experiment actually found, not filler:
A-0 shows sharing going through PostgreSQL rather than between the caches;
A-3 the gap between the 200 and the WAL flush, with both failed injections;
A-5 the three silent injection failures; A-6 the two places latency is
multiplied; B-0 the repository keyed by principal with no session id; B-2
the primary key that causes the overwrite; D-2 why the rolling update
stopped the accident halfway.

Also corrected the index's stale claim of 11 experiments without a
screenshot — it is 14, and the reason is recorded: those experiments were
measured from terminals, the database and logs, and the observability stack
does not scrape Redis, the BFF or PostgreSQL, so there is no console to
photograph.

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

docs/diagrams/b0-autoconfiguration.svg

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+<text x="20" y="26" class="ttl">B-0 — 아무것도 설정하지 않으면 Spring 이 무엇을 고르는가</text>
+<text x="20" y="44" class="s">추측이 맞았지만, 추측으로 두면 안 되는 이유가 둘째 줄에 있다</text>
+<rect x="30" y="72" width="800" height="118" class="box"/>
+<text x="46" y="94" class="tb">/actuator/beans 가 실제로 답한 것</text>
+<text x="46" y="118" class="t">authorizedClientService      → InMemoryOAuth2AuthorizedClientService</text>
+<text x="46" y="138" class="t">authorizedClientRepository   → AuthenticatedPrincipalOAuth2AuthorizedClientRepository</text>
+<text x="46" y="158" class="t">SessionRepository            → 없음 (서블릿 컨테이너 in-memory)</text>
+<text x="46" y="178" class="t" fill="#cf222e">Redis / Spring Session       → 없음</text>
+<rect x="30" y="212" width="390" height="150" class="warn"/>
+<text x="46" y="234" class="tb">★ 이름이 곧 설명이다</text>
+<text x="46" y="256" class="s">AuthenticatedPrincipal…Repository 는</text>
+<text x="46" y="276" class="t">principal 이름으로 찾는다</text>
+<rect x="46" y="288" width="358" height="30" class="dead"/>
+<text x="58" y="308" class="s">조회 키에 session id 가 없다</text>
+<text x="46" y="336" class="s">그래서 세션 저장소를 Redis 로 옮겨도</text>
+<text x="46" y="354" class="s">토큰은 따라오지 않는다 — B-1 이 겪는 문제의 뿌리</text>
+<rect x="440" y="212" width="390" height="150" class="box"/>
+<text x="456" y="234" class="tb">두 개가 서로 다른 것을 저장한다</text>
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+<text x="468" y="266" class="t">Application Session</text>
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+<text x="468" y="316" class="t">OAuth2AuthorizedClient</text>
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+<text x="456" y="356" class="s">이 둘을 하나로 생각하면 B-1·B-2 의 결과를 해석할 수 없다</text>
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