Compute batching (#849)

### Compute Batch Submission
- Consolidate duplicated action submission logic in `httpcomputeservice` into a single `HandleSubmitAction` supporting both single-action and batch (actions array) payloads
- Group actions by queue in `RemoteHttpRunner` and submit as batches with configurable chunk size, falling back to individual submission on failure
- Extract shared helpers: `MakeErrorResult`, `ValidateQueueForEnqueue`, `ActivateActionInQueue`, `RemoveActionFromActiveMaps`

### Retracted Action State
- Add `Retracted` state to `RunnerAction` for retry-free rescheduling — an explicit request to pull an action back and reschedule it on a different runner without incrementing `RetryCount`
- Implement idempotent `RetractAction()` on `RunnerAction` and `ComputeServiceSession`
- Add `POST jobs/{lsn}/retract` and `queues/{queueref}/jobs/{lsn}/retract` HTTP endpoints
- Add state machine documentation and per-state comments to `RunnerAction`

### Compute Race Fixes
- Fix race in `HandleActionUpdates` where actions enqueued between session abandon and scheduler tick were never abandoned, causing `GetActionResult` to return 202 indefinitely
- Fix queue `ActiveCount` race where `NotifyQueueActionComplete` was called after releasing `m_ResultsLock`, allowing callers to observe stale counters immediately after `GetActionResult` returned OK

### Logging Optimization and ANSI improvements
- Improve `AnsiColorStdoutSink` write efficiency — single write call, dirty-flag flush, `RwLock` instead of `std::mutex`
- Move ANSI color emission from sink into formatters via `Formatter::SetColorEnabled()`; remove `ColorRangeStart`/`End` from `LogMessage`
- Extract color helpers (`AnsiColorForLevel`, `StripAnsiSgrSequences`) into `helpers.h`
- Strip upstream ANSI SGR escapes in non-color output mode. This enables colour in log messages without polluting log files with ANSI control sequences
- Move `RotatingFileSink`, `JsonFormatter`, and `FullFormatter` from header-only to pimpl with `.cpp` files

### CLI / Exec Refactoring
- Extract `ExecSessionRunner` class from ~920-line `ExecUsingSession` into focused methods and a `ExecSessionConfig` struct
- Replace monolithic `ExecCommand` with subcommand-based architecture (`http`, `inproc`, `beacon`, `dump`, `buildlog`)
- Allow parent options to appear after subcommand name by parsing subcommand args permissively and forwarding unmatched tokens to the parent parser

### Testing Improvements
- Fix `--test-suite` filter being ignored due to accumulation with default wildcard filter
- Add test suite banners to test listener output
- Made `function.session.abandon_pending` test more robust

### Startup / Reliability Fixes
- Fix silent exit when a second zenserver instance detects a port conflict — use `ZEN_CONSOLE_*` for log calls that precede `InitializeLogging()`
- Fix two potential SIGSEGV paths during early startup: guard `sentry_options_new()` returning nullptr, and throw on `ZenServerState::Register()` returning nullptr instead of dereferencing
- Fail on unrecognized zenserver `--mode` instead of silently defaulting to store

### Other
- Show host details (hostname, platform, CPU count, memory) when discovering new compute workers
- Move frontend `html.zip` from source tree into build directory
- Add format specifications for Compact Binary and Compressed Buffer wire formats
- Add `WriteCompactBinaryObject` to zencore
- Extended `ConsoleTui` with additional functionality
- Add `--vscode` option to `xmake sln` for clangd / `compile_commands.json` support
- Disable compute/horde/nomad in release builds (not yet production-ready)
- Disable unintended `ASIO_HAS_IO_URING` enablement
- Fix crashpad patch missing leading whitespace
- Clean up code triggering gcc false positives

1 files changed, 42 insertions, 11 deletions

diff --git a/src/zencompute/runners/functionrunner.h b/src/zencompute/runners/functionrunner.h
index f67414dbb..56c3f3af0 100644
--- a/src/zencompute/runners/functionrunner.h
+++ b/src/zencompute/runners/functionrunner.h
@@ -29,8 +29,8 @@ public:
 	FunctionRunner(std::filesystem::path BasePath);
 	virtual ~FunctionRunner() = 0;
 
-	virtual void Shutdown()										= 0;
-	virtual void RegisterWorker(const CbPackage& WorkerPackage) = 0;
+	virtual void			   Shutdown()									  = 0;
+	[[nodiscard]] virtual bool RegisterWorker(const CbPackage& WorkerPackage) = 0;
 
 	[[nodiscard]] virtual SubmitResult				SubmitAction(Ref<RunnerAction> Action) = 0;
 	[[nodiscard]] virtual size_t					GetSubmittedActionCount()			   = 0;
@@ -63,7 +63,7 @@ public:
 	SubmitResult			  SubmitAction(Ref<RunnerAction> Action);
 	std::vector<SubmitResult> SubmitActions(const std::vector<Ref<RunnerAction>>& Actions);
 	size_t					  GetSubmittedActionCount();
-	void					  RegisterWorker(CbPackage Worker);
+	[[nodiscard]] bool		  RegisterWorker(CbPackage Worker);
 	void					  Shutdown();
 	bool					  CancelAction(int ActionLsn);
 	void					  CancelRemoteQueue(int QueueId);
@@ -114,6 +114,30 @@ struct RunnerGroup : public BaseRunnerGroup
 
 /**
  * This represents an action going through different stages of scheduling and execution.
+ *
+ * State machine
+ * =============
+ *
+ * Normal forward flow (enforced by SetActionState rejecting backward transitions):
+ *
+ *   New -> Pending -> Submitting -> Running -> Completed
+ *                                           -> Failed
+ *                                           -> Abandoned
+ *                                           -> Cancelled
+ *
+ * Rescheduling (via ResetActionStateToPending):
+ *
+ *   Failed    ---> Pending   (increments RetryCount, subject to retry limit)
+ *   Abandoned ---> Pending   (increments RetryCount, subject to retry limit)
+ *   Retracted ---> Pending   (does NOT increment RetryCount)
+ *
+ * Retraction (via RetractAction, idempotent):
+ *
+ *   Pending/Submitting/Running -> Retracted -> Pending (rescheduled)
+ *
+ * Retracted is placed after Cancelled in enum order so that once set,
+ * no runner-side transition (Completed/Failed) can override it via
+ * SetActionState's forward-only rule.
  */
 struct RunnerAction : public RefCounted
 {
@@ -137,16 +161,20 @@ struct RunnerAction : public RefCounted
 
 	enum class State
 	{
-		New,
-		Pending,
-		Submitting,
-		Running,
-		Completed,
-		Failed,
-		Abandoned,
-		Cancelled,
+		New,		 // Initial state at construction, before entering the scheduler
+		Pending,	 // Queued and waiting for a runner slot
+		Submitting,	 // Being handed off to a runner (async submission in progress)
+		Running,	 // Executing on a runner process
+		Completed,	 // Finished successfully with results available
+		Failed,		 // Execution failed (transient error, eligible for retry)
+		Abandoned,	 // Infrastructure termination (e.g. spot eviction, session abandon)
+		Cancelled,	 // Intentional user cancellation (never retried)
+		Retracted,	 // Pulled back for rescheduling on a different runner (no retry cost)
 		_Count
 	};
+	static_assert(State::Retracted > State::Completed && State::Retracted > State::Failed && State::Retracted > State::Abandoned &&
+					  State::Retracted > State::Cancelled,
+				  "Retracted must be the highest terminal ordinal so runner-side transitions cannot override it");
 
 	static const char* ToString(State _)
 	{
@@ -168,6 +196,8 @@ struct RunnerAction : public RefCounted
 				return "Abandoned";
 			case State::Cancelled:
 				return "Cancelled";
+			case State::Retracted:
+				return "Retracted";
 			default:
 				return "Unknown";
 		}
@@ -191,6 +221,7 @@ struct RunnerAction : public RefCounted
 	void  SetActionState(State NewState);
 
 	bool IsSuccess() const { return ActionState() == State::Completed; }
+	bool RetractAction();
 	bool ResetActionStateToPending();
 	bool IsCompleted() const
 	{