chore: record pre-existing uncommitted repository state

Snapshot of the in-flight state that already existed, identically, in both
this worktree and the main checkout before this session began: the initial
HTTP Client platform implementation (previously untracked), the redis-lab
removal, and the JPA / object-storage / notification integration work.

Kept separate from this session's HTTP Client review response, which lands
in the following commit, so the two bodies of work stay reviewable apart.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

infra/httpclient/proxy/README.md

@@ -0,0 +1,12 @@
+# Forward proxy fixture
+
+`ProxyFixture` runs an in-process forward proxy so the proxy lane needs no external service.
+
+| Factory | Behaviour |
+|---|---|
+| `ProxyFixture.openProxy()` | accepts CONNECT and tunnels to the target |
+| `ProxyFixture.authenticatingProxy(user, password)` | answers `407` until `Proxy-Authorization` matches |
+
+The fixture records every request line and every `Proxy-Authorization` value it saw, which is what
+lets the suite prove design §24.3: proxy credentials never appear on the target request, and a proxy
+CONNECT failure is reported as `HttpProxyException` rather than as a target TLS failure.