Add scoped semantic logging for WebSocket, MQTT, and Express

[VolkerChristian]

Motivation

• Resolve the remaining 26 FOLLOW_UP_SCOPED_HELPER_DESIGN audit rows (CSI-P075–CSI-P084, CSI-P135–CSI-P142, CSI-P143–CSI-P150) by adding the smallest safe connection-scoped semantic-logging helpers and migrating only the audited call sites.
• Ensure structured identity (inst= and conn=) is copied from the active SocketConnection before removing duplicated connection-name prefixes from free-text messages.
• Preserve existing zero-argument helpers and the existing semantic logging abstractions (LogScopeOwner, BoundaryLogger) while avoiding global/thread-local identity or exposing spdlog types.

Description

• Added narrow connection-scoped overloads that copy identity from core::socket::stream::SocketConnection and produce a BoundaryLogger via LogScopeOwner for each surface: webSocketSubProtocolLog(const SocketConnection&), mqttWebSocketLog(const SocketConnection&), and expressLog(const SocketConnection&), reusing existing logging primitives and owning only copied strings.
• Migrated the 26 audited call sites to the new scoped helpers (WebSocket SubProtocol and SocketContextUpgrade, MQTT SubProtocol, Express StaticMiddleware / VerboseRequest and Router/Application/Middleware dispatchers) and removed the duplicated connection-name prefix from free-text messages while preserving substantive content (and adding short non-empty messages where the old text was identity-only).
• Added a focused runtime test ScopedSemanticLoggingMigrationTest that emits scoped and unscoped records and verifies origin/boundary/component preservation, instance/connection population, message-text changes, multiline MQTT frame-data preservation, and zero-argument helper compatibility.
• Updated the audit document docs/logging/semantic-identity-callsite-audit.md with a concise Resolution status table documenting CSI-P075–CSI-P084, CSI-P135–CSI-P142, and CSI-P143–CSI-P150 as resolved by this branch; no unrelated KEEP/REMOVE_LATER rows were changed.

Testing

• Configured and generated the build with tests enabled using cmake -S . -B build -DSNODEC_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE=Debug; summary: Configuring done; Generating done; Build files have been written to: /workspace/snode.c/build.
• Built focused targets including the semantic logging tests and subsystem targets with cmake --build build --target websocket websocket-server websocket-client mqtt mqtt-client-websocket mqtt-server-websocket http-server-express ScopedSemanticLoggingMigrationTest WebSocketMigration07cTest MqttMigration08Test -j2; build completed and produced the expected targets (for example [100%] Built target MqttMigration08Test).
• Ran the focused scoped test: ctest --test-dir build -R ScopedSemanticLoggingMigrationTest --output-on-failure which passed: 100% tests passed, 0 tests failed out of 1.
• Ran a representative combined test selection: ctest --test-dir build -R "ScopedSemanticLoggingMigrationTest|WebSocketMigration07cTest|MqttMigration08Test|Semantic(LoggerRound2|CompatibilityRound9|BackendRound6|FilterRound7)|InetExpress(...)|WebSocketReceiverValidationTest|InetWebSocketServerClient(...)|Mqtt311PacketValidationTest" --output-on-failure and observed 100% tests passed, 0 tests failed out of 22 with several component tests reported as skipped by CTest in this container; the focused semantic tests and related migration tests passed.

(Changed files and the focused test are included in the branch; build and test outputs above are the exact final summary lines produced during verification.)

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Codex Task