Update Cotabby for single-sequence inference

AGENTS.md

@@ -160,6 +160,10 @@ Runtime generation is split by responsibility:
 cache/decode, and shutdown work serialized while heavy generation runs away from MainActor. The
 manager should publish state; the core should own native correctness.
 
+Cotabby owns one autocomplete sequence. CotabbyInference therefore exposes one live native sequence
+backed by llama.cpp slot zero; a changing external sequence ID rejects stale handles after reset.
+The Swift generation loop owns the maximum output-token budget.
+
 ## UI And Overlays
 
 - `OverlayController` owns the ghost-text panel lifecycle and positioning.

ARCHITECTURE.md

@@ -239,6 +239,10 @@ LlamaRuntimeCore is a nonisolated lock/condition-protected native boundary, not
 autocomplete lock serializes cache/decode state, and its lifecycle condition prevents shutdown from
 racing active native work. Heavy work runs away from MainActor.
 
+The app and CotabbyInference intentionally expose one live autocomplete sequence. The package uses
+one llama.cpp sequence slot and a changing external ID to reject stale work after a reset; the Swift
+generation loop remains the single owner of the output-token budget.
+
 [BaseCompletionPromptRenderer.swift](Cotabby/Support/Prompting/BaseCompletionPromptRenderer.swift) renders a
 base-model text continuation with optional budgeted context and the caret prefix last. It does not
 wrap a base GGUF in an instruction conversation. [FoundationModelPromptRenderer.swift](Cotabby/Support/Prompting/FoundationModelPromptRenderer.swift)

Cotabby/Services/Runtime/LlamaRuntimeCore.swift

@@ -4,13 +4,14 @@ import CotabbyInference
 
 /// File overview:
 /// Owns the C++ inference engine and manages the autocomplete KV cache lifecycle. This is the
-/// lowest-level runtime boundary in the app: it loads the GGUF model, manages concurrent
-/// sequences, tokenizes prompts, samples continuations, and frees native resources on shutdown.
+/// lowest-level runtime boundary in the app: it loads the GGUF model, owns Cotabby's single
+/// autocomplete sequence, tokenizes prompts, samples continuations, and frees native resources on
+/// shutdown.
 ///
-/// The engine handles thread safety internally via per-sequence mutexes. This class is
-/// `@unchecked Sendable` rather than an `actor` so native work can execute away from MainActor.
-/// `autocompleteLock` serializes autocomplete-specific KV-cache state. A separate
-/// `lifecycleCondition` prevents `shutdown()` from unloading the model while generation is in flight.
+/// The engine serializes its one mutable llama context internally. This class is `@unchecked
+/// Sendable` rather than an `actor` so native work can execute away from MainActor.
+/// `autocompleteLock` serializes autocomplete-specific KV-cache state, while a separate
+/// `lifecycleCondition` prevents `shutdown()` from unloading the model during generation.
 
 /// Immutable runtime metadata captured after a model has been successfully prepared.
 struct PreparedLlamaRuntime: Sendable {
@@ -717,16 +718,18 @@ nonisolated final class LlamaRuntimeCore: @unchecked Sendable {
     private static let defaultSamplerSeed: UInt32 = 0x00C0_FFEE
 
     private static func samplingConfig(from options: LlamaGenerationOptions) -> SamplingConfig {
-        SamplingConfig(
-            max_prediction_tokens: Int32(options.maxPredictionTokens),
-            temperature: Float(options.temperature),
-            top_k: Int32(options.topK),
-            top_p: Float(options.topP),
-            min_p: Float(options.minP),
-            repetition_penalty: Float(options.repetitionPenalty),
-            seed: options.seed ?? Self.defaultSamplerSeed,
-            single_line: options.singleLine
-        )
+        // Assign the fields after default construction so the app remains source-compatible while
+        // CotabbyInference removes native configuration fields that Swift never consumed. C++
+        // aggregate memberwise initializers otherwise require every imported field at the call site.
+        var config = SamplingConfig()
+        config.temperature = Float(options.temperature)
+        config.top_k = Int32(options.topK)
+        config.top_p = Float(options.topP)
+        config.min_p = Float(options.minP)
+        config.repetition_penalty = Float(options.repetitionPenalty)
+        config.seed = options.seed ?? Self.defaultSamplerSeed
+        config.single_line = options.singleLine
+        return config
     }
 
     private static func reusableTokenCount(commonTokenPrefix: Int, newPromptTokenCount: Int) -> Int {