Merge branch 'develop'

* develop: (55 commits)
  chore(release): prepare for 0.0.13
  test: extend path-validation state transition regressions
  docs: expand README with practical client/server examples
  test: add RTT ack-delay boundary and empty-ack regressions
  test: extend recovery gate and persistent-reset model vectors
  test: add strict loss-time threshold boundary regression
  test: add repeated-loss floor and post-reset growth vectors
  test: expand packet bookkeeping and sent-history lifecycle vectors
  test: add MAX_STREAMS and MAX_STREAM_DATA monotonic regressions
  test: add PTO noop and path validation replacement regressions
  test: add ACK-round retransmission queue ordering regression
  test: cover replayed-ack loss frontier progression
  test: add path validation queue and mismatch regressions
  test: add max-observed and explicit-ack-list regressions
  test: add amplification saturation and budget-min regressions
  test: cover PTO non-ack deadline and probe sizing
  test: add PTO probe queue and deadline refresh regressions
  test: add congestion residual-ack and reset-state regressions
  test: add sent-history isolation and unsent-ack semantics
  test: add PTO reset and backoff-cap regressions
  ...

Author: bresilla

ACKNOWLEDGMENTS.md

@@ -0,0 +1,12 @@
+# Acknowledgements
+
+Some codebases are references. Some are reality checks. LSQUIC was both.
+
+libfast's transport-level parity work benefited massively from studying and
+cross-checking against LSQUIC behavior and tests.
+
+- **[LSQUIC](https://github.com/litespeedtech/lsquic)**
+- **Docs**: https://lsquic.readthedocs.io/
+
+Thank you to the LSQUIC project for publishing rigorous QUIC work openly - it
+made this library better.

CHANGELOG.md

@@ -1,5 +1,78 @@
 # Changelog
 
+## [0.0.13] - 2026-03-02
+
+### <!-- 1 -->🐛 Bug Fixes
+
+- Enforce strict drain deadline expiry semantics
+
+### <!-- 2 -->🚜 Refactor
+
+- Split connection CID and reset tests into module
+- Split connection retry/VN tests into dedicated module
+- Split connection frame-legality tests into separate file
+
+### <!-- 3 -->📚 Documentation
+
+- Expand README with practical client/server examples
+- Add concise lsquic acknowledgment
+- Thank lsquic project and contributors
+
+### <!-- 6 -->🧪 Testing
+
+- Extend path-validation state transition regressions
+- Add RTT ack-delay boundary and empty-ack regressions
+- Extend recovery gate and persistent-reset model vectors
+- Add strict loss-time threshold boundary regression
+- Add repeated-loss floor and post-reset growth vectors
+- Expand packet bookkeeping and sent-history lifecycle vectors
+- Add MAX_STREAMS and MAX_STREAM_DATA monotonic regressions
+- Add PTO noop and path validation replacement regressions
+- Add ACK-round retransmission queue ordering regression
+- Cover replayed-ack loss frontier progression
+- Add path validation queue and mismatch regressions
+- Add max-observed and explicit-ack-list regressions
+- Add amplification saturation and budget-min regressions
+- Cover PTO non-ack deadline and probe sizing
+- Add PTO probe queue and deadline refresh regressions
+- Add congestion residual-ack and reset-state regressions
+- Add sent-history isolation and unsent-ack semantics
+- Add PTO reset and backoff-cap regressions
+- Add PTO deadline and retransmission ordering regressions
+- Add drain timeout clamp boundary regressions
+- Add ACK ordering and replay idempotence regressions
+- Add recovery exit and window boundary vectors
+- Cover recovery epoch rollover and inflight saturation
+- Add congestion avoidance ack-growth vector
+- Add congestion lifecycle stability regression
+- Add mixed ACK-loss send lifecycle regression
+- Add packet bookkeeping interop vectors
+- Add packet buffer capacity ladder interop vectors
+- Add lsquic stream frame generation vectors
+- Keep latest NEW_TOKEN across multi-frame packet
+- Add lsquic packet header generation vectors
+- Add lsquic RTT progression parity vector
+- Add ack-merge duplicate packet regression
+- Add lsquic varint and ACK capacity interop vectors
+- Expand interop module with ACK and short-header truncation
+- Add malformed VN vectors to interop module
+- Add dedicated lsquic interop vector module
+- Add lsquic-style control-frame truncation matrix
+- Add lsquic-style ACK truncation corpus
+- Add lsquic-style packet truncation decode corpus
+- Extend lsquic ACK sparse and packet-number vectors
+- Extend malformed packet corpus for oversized CID lengths
+- Add lsquic ACK and packet-number compatibility vectors
+- Add lsquic compatibility vectors for varint and VN
+
+### <!-- 7 -->⚙️ Miscellaneous Tasks
+
+- Gate live lsquic interop behind env toggle
+
+### Build
+
+- Add optional live lsquic interop harness target
+
 ## [0.0.12] - 2026-03-01
 
 ### <!-- 0 -->⛰️  Features

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build test test-dual-mode ci install
+.PHONY: build test test-dual-mode interop-live ci install
 
 build:
 	zig build -Doptimize=ReleaseFast
@@ -9,9 +9,13 @@ test:
 test-dual-mode:
 	zig build test-dual-mode-regression --summary all
 
+interop-live:
+	./tools/lsquic_live_interop.sh
+
 ci:
 	zig build test-dual-mode-regression --summary all
 	zig build test --summary all
+	@if [ "$(LIBFAST_RUN_LIVE_INTEROP)" = "1" ]; then ./tools/lsquic_live_interop.sh; else echo "Skipping live LSQUIC interop (set LIBFAST_RUN_LIVE_INTEROP=1 to enable)"; fi
 	zig build -Doptimize=ReleaseFast
 
 install: build

PROJECT

@@ -1,2 +1,2 @@
 libfast
-0.0.12
+0.0.13

README.md

@@ -71,9 +71,29 @@ pub fn main() !void {
     defer conn.deinit();
 
     // Connect and use streams
-    try conn.connect("192.0.2.1:4433");
-    var stream = try conn.openStream();
-    try stream.write("Hello, QUIC!");
+    try conn.connect("192.0.2.1", 4433);
+
+    // Your app drives progress by polling.
+    while (true) {
+        try conn.poll();
+
+        while (conn.nextEvent()) |ev| switch (ev) {
+            .connected => {
+                const sid = try conn.openStream(true);
+                _ = try conn.streamWrite(sid, "Hello over QUIC", .no_finish);
+            },
+            .stream_readable => |sid| {
+                var buf: [1024]u8 = undefined;
+                const n = try conn.streamRead(sid, &buf);
+                std.debug.print("stream {} read {s}\n", .{ sid, buf[0..n] });
+            },
+            .closing => |c| {
+                std.debug.print("closing: {d} {s}\n", .{ c.error_code, c.reason });
+            },
+            .closed => return,
+            else => {},
+        };
+    }
 }
 ```
 
@@ -88,6 +108,30 @@ var conn = try libfast.QuicConnection.init(allocator, config);
 // ... rest is identical
 ```
 
+### Usage Example (Server Loop)
+
+```zig
+const config = libfast.QuicConfig.sshServer("obfuscation-keyword");
+var conn = try libfast.QuicConnection.init(allocator, config);
+defer conn.deinit();
+
+try conn.accept("0.0.0.0", 4433);
+
+while (true) {
+    try conn.poll();
+
+    while (conn.nextEvent()) |ev| switch (ev) {
+        .stream_readable => |sid| {
+            var buf: [2048]u8 = undefined;
+            const n = try conn.streamRead(sid, &buf);
+            _ = try conn.streamWrite(sid, buf[0..n], .no_finish); // echo
+        },
+        .closed => return,
+        else => {},
+    };
+}
+```
+
 ## Project Structure
 
 ```
@@ -136,12 +180,17 @@ lib/
 
 Build the library:
 ```bash
-zig build
+make build
 ```
 
 Run tests:
 ```bash
-zig build test
+make test
+```
+
+Run dual-mode regression tests:
+```bash
+make test-dual-mode
 ```
 
 Run examples:
@@ -154,7 +203,7 @@ zig build run-tls-client
 
 ## Testing
 
-200+ unit tests covering:
+500+ unit tests covering:
 - Core protocol (packets, frames, streams)
 - SSH crypto (obfuscation, key exchange)
 - TLS crypto (handshake, key schedule)
@@ -190,12 +239,11 @@ zig build test --summary all
 - Documentation
 
 ### Future Enhancements
-- Path validation and migration
-- Full integration testing
-- Performance optimization
-- Interoperability testing
-- TLS certificate validation
-- Out-of-order packet buffering
+- Congestion-control model expansion (Cubic/BW-sampler parity vectors)
+- Additional live interop lanes and environment matrix coverage
+- Performance profiling and optimization
+- TLS certificate validation hardening
+- Extended end-to-end scenario testing
 
 ## Dependencies
 

build.zig.zon

@@ -1,6 +1,6 @@
 .{
     .name = .libfast,
-    .version = "0.0.12",
+    .version = "0.0.13",
     .dependencies = .{
         // zquic removed - building custom minimal QUIC for SSH/QUIC
     },