Add managed codec DSP and initial control server

PROGRESS.md

@@ -10,6 +10,139 @@ up instantly. Newest status at the top.
 
 ## ▶ Where we left off / next action
 
+- **In progress (2026-09-15): Phase 4 managed server control plane.** Added TLS socket
+  orchestration, bounded framing/queues, guest and password authentication, persisted
+  channels, state snapshots, channel joins, text routing, ping and disconnect events.
+  The existing C++ CLI authenticates and sends text through the managed server.
+  Managed Argon2id verification passes libsodium fixtures, including UTF-8 and embedded
+  NUL passwords. The C++ database oracle proves existing account/channel import and
+  C++ verification of managed-created accounts without password resets. **Verified:**
+  142/142 managed tests with all native interoperability checks enabled, warning-free
+  Release build, regenerated password fixtures identical, and 22 permissive package
+  licenses; native dev build and 29/29 CTest tests green. Locked restore passes.
+  CI requires CLI/database checks in its C++ conformance job. Codec/DSP and the first
+  server slice are committed together on `dotnet/foundations` as a validated checkpoint.
+  **Next:** encrypted UDP binding/SFU relay and stream signaling.
+  UDP voice, streams, administration, protected channel joins and production configuration
+  remain pending; this is the first control-plane checkpoint, not Phase 4 completion.
+
+### .NET handoff / discoveries (2026-09-15)
+
+- **Working tree:** stay on `dotnet/foundations`, tracking `origin/dotnet/foundations`.
+  Foundation `b76181d` and TLS checkpoint `2df79cd` were committed and pushed.
+  The codec/DSP port and first managed server checkpoint were subsequently committed
+  together, including new projects, native bindings/oracles, tests and docs.
+  See the latest checkpoint commit; no push is requested for this session.
+- **Style/scope:** write idiomatic .NET in `dotnet/`; do not copy C++ code or comment
+  style. The existing implementation is the behavior/wire oracle. No wire changes
+  were made. Read `docs/porting-to-dotnet.md`, `docs/api-dotnet.md`, `dotnet/README.md`
+  and the relevant protocol/security/voice sections before the next subsystem.
+- **Implemented projects:** `VoiceCat.Protocol` (existing protobuf + framing),
+  `VoiceCat.Crypto` (media crypto/replay, TLS/exporters, identity/TOFU, password hashing),
+  `VoiceCat.Codec` (Opus/PLC/DRED), `VoiceCat.Dsp` (RNNoise/energy VAD), and
+  `VoiceCat.Server` (real TLS control server + compatible SQLite account/channel store).
+  `dotnet/oracle/` contains optional native wire, TLS, DSP, password and database
+  conformance executables. `ServerTests` exercises real sockets and the existing CLI;
+  `AccountStoreTests` proves native database import and password verification both ways.
+- **TLS discovery:** BouncyCastle destroys exporter secrets after its handshake
+  callback. Export keys inside `NotifyHandshakeComplete`, not after the socket loop
+  notices readiness. Preserve label `voicecat media v1` and contexts `[0]` / `[1]`.
+  A `TlsSession` has one owner; the control connection loop owns all TLS calls.
+  Certificate acceptance is a synchronous leaf-SHA256 pin gate, not normal PKI.
+  New certificates carry the Ed25519 public key in their SAN, but verification of
+  the ServerHello identity against that SAN remains pending. Partial credential
+  sets must fail rather than silently generate a new server identity.
+- **Native codec discoveries:** the actual pinned Opus is **1.5.2**, despite older
+  design comments referring to 1.6. Standalone builds use checksum-pinned upstream
+  sources with DRED/Deep PLC enabled. DRED needs a **30 ms minimum** in this release;
+  20 ms produces no redundancy. DRED encoding at 8/12 kHz is explicitly unsupported;
+  decoding works at all five rates. Recovery offset defaults to one missing frame's
+  samples before the next packet's start (the older C++ zero offset is not a guide).
+  Fixed-signature C wrappers avoid the Apple ARM64 varargs ABI issue with Opus CTLs.
+  Windows DLL staging must omit the MinGW `lib` prefix. MinGW and MSVC builds pass;
+  iOS needs later static packaging. Device audio callbacks/rings are not implemented.
+- **DSP behavior:** RNNoise processes complete 480-sample mono chunks at 48 kHz;
+  other rates pass through, and partial chunks at 48 kHz are rejected. Native C++
+  conformance allows one PCM unit for rounding. VAD hang time uses monotonic
+  `TimeProvider` timestamps, starts closed and does not replace noise suppression.
+  The combined allocation test proves zero managed allocations across 1,000 cycles.
+- **Password/database discoveries:** use the existing BouncyCastle Argon2 engine
+  with strict libsodium PHC parsing; no additional Konscious dependency or password
+  reset is needed. Keep UTF-8 bytes unchanged, including embedded NUL. New hashes use
+  Argon2id v19, 64 MiB, two iterations, parallelism one, salt 16/output 32 bytes.
+  Verification is bounded to 128 MiB, ten iterations, parallelism four and 1024 UTF-8
+  password bytes; excessive imported costs fail closed. Two per-store password
+  workers bound CPU/memory use. Failed login does not update `last_login`.
+  Keep SQLite schema v2; accept v1 migration and reject unknown versions.
+  **Seed both default channels only when the entire channel table is empty**;
+  an existing single Lobby is an intentional configuration and must be preserved.
+- **SQLite dependency discovery:** the initial `Microsoft.Data.Sqlite` 10.0.5 bundle
+  pulled an older vulnerable SQLite native dependency, rejected by warnings-as-errors
+  restore. The implementation uses `Microsoft.Data.Sqlite.Core` 10.0.5,
+  SQLitePCLRaw bundle 3.0.2 and explicitly pinned SourceGear SQLite 3.50.4.2 instead.
+  SourceGear's native package lacks a NuGet license expression; the audit has an
+  exact-version/repository-identity exception for its public-domain SQLite build.
+  NativeAOT publishing/trimming has not been verified for this solution.
+- **Server checkpoint limits:** CLI binds loopback; positional arguments are data
+  directory and TCP port. Guests are enabled there, and the hosting API can disable
+  them. Accounts can be provisioned through `AccountStore` or native administration;
+  automatic bootstrap/admin CLI is pending. Authentication enters unprotected Lobby
+  id 1 subject to capacity. Server owns text sender ids/timestamps. Connections cap
+  at 64; queues cap at 32 incoming/64 outgoing envelopes, payloads at 64 KiB (shared
+  framer allows 16 MiB). Slow consumers disconnect. TLS handshake timeout is 15 s;
+  receive-idle timeout after handshake is 60 s. No UDP port/media features are
+  advertised, and voice subscription fails explicitly. Protected joins, channel CRUD,
+  streams, SFU, moderation/admin handlers, configuration compatibility and full reaper
+  behavior remain pending. **Do not mark Phase 4 or voice interoperability complete.**
+
+To reproduce the last successful validation on Windows, run in **PowerShell**:
+
+```powershell
+./dotnet/build-native.ps1 -Generator Ninja -CCompiler C:/tools/msys64/ucrt64/bin/cc.exe
+cmake --preset dev -DVOICECAT_BUILD_DOTNET_ORACLE=ON
+cmake --build --preset dev
+ctest --preset dev
+dotnet restore dotnet/VoiceCat.slnx --locked-mode
+$env:VOICECAT_TLS_ORACLE = (Resolve-Path build/dev/bin/voicecat-dotnet-tls-oracle.exe).Path
+$env:VOICECAT_DATABASE_ORACLE = (Resolve-Path build/dev/bin/voicecat-dotnet-database-oracle.exe).Path
+$env:VOICECAT_VCCLI = (Resolve-Path build/dev/bin/vccli.exe).Path
+dotnet test dotnet/VoiceCat.slnx -c Release --no-restore
+./dotnet/check-licenses.ps1
+```
+
+Last results: **142/142 managed tests, no skips with those variables set; 29/29 native
+CTest tests; warning-free Release build; 22 package licenses approved; locked restore
+and `git diff --check` passed.** Without the variables, native interoperability tests
+skip; that is not equivalent verification. Desktop CI stages codec/DSP bindings on
+Windows/Linux/macOS. Its Linux C++ job requires TLS, CLI and database interoperability
+and regenerates wire/password/DSP fixtures. Only Windows was run locally this session.
+
+**Next behavior to implement:** read `docs/protocol.md`, `docs/security.md` and the
+existing UDP binding/relay/session handlers. Write a real-client test for authenticated
+UDP binding and encrypted relay between two clients, preserving SSRC/timestamp/flags
+and encoded Opus while resealing with each recipient's directional key/counter.
+Then implement binding tokens, stream announce/stop/subscription and channel routing.
+Reject unauthenticated/replayed media and verify channel/subscription isolation.
+Never decode audio on the SFU. Phase 4 exits only when two existing C++ clients can
+exchange voice through the managed server as well as authenticate, join and chat.
+
+- **Done (2026-09-15): Codec/DSP desktop port.** TLS checkpoint `2df79cd` committed
+  and pushed to `origin/dotnet/foundations`. Added span-based Opus wrappers, safe native
+  handle ownership, RNNoise processing, monotonic energy VAD, and fixed-signature
+  native bindings. Round-trip/PLC behavior passes across 40 supported formats with
+  the existing Opus build. Independent native staging builds checksum-pinned upstream
+  Opus 1.5.2 with DRED enabled and the existing RNNoise model. Actual dropped-frame
+  DRED recovery passes across 40 decoder formats; DRED encoding at 8/12 kHz is
+  explicitly rejected (tests encode those packets at 16 kHz). This release requires
+  a 30 ms redundancy floor; the older 20 ms setting emits no DRED. C++ denoising
+  conformance is within one PCM unit, and 1,000 codec/DSP cycles allocate zero managed
+  bytes. **Verified:** Release build with no warnings; 127/127 managed tests with
+  native TLS interoperability enabled; native dev build and 29/29 CTest tests green;
+  16 permissive NuGet licenses. MinGW and Visual Studio native builds pass. Desktop
+  CI now builds/stages the bindings before testing. iOS static packaging and device
+  audio remain later phases. **Next:** Phase 4 managed server; prove persisted
+  libsodium Argon2id hash compatibility before account/database implementation.
+
 - **Done (2026-09-15): TLS exporter interoperability and persisted credentials.** Foundation commit
   `b76181d` pushed to `origin/dotnet/foundations`. Added a nonblocking managed TLS 1.3
   session with certificate acceptance gate and directional media factories. Managed