invert dependency: internal no longer imports internal/tui

Introduce internal/runtime as a neutral contract package that both the
core engine (internal) and the TUI layer (internal/tui) depend on.

- internal/runtime: defines TraceStarter, StreamSource, EventSink,
  LiveTrieSource, SnapshotSource, ProbeManager, RuntimePublisher,
  RuntimeState, TraceRuntimeBindings, and all context key/helper
  functions (RuntimeBindingsFromContext, RuntimePublisherFromContext,
  ContextWithRuntimeBindings, ContextWithTraceFilters,
  TraceFiltersFromContext). These were previously defined in
  internal/tui, forcing the core package to import the TUI layer.

- internal/streamrow: add RingBuffer (moved from internal/tui/eventstream)
  so the core tracing engine can use the ring buffer without importing
  the TUI layer.

- internal/tui/eventstream/ringbuffer.go: change to a thin re-export of
  streamrow.RingBuffer via a type alias, preserving the existing API for
  all callers within the TUI layer.

- internal/tui/tui.go: replace locally-defined interface declarations
  (TraceStarter, SnapshotSource, ProbeManager, RuntimePublisher,
  RuntimeState, TraceRuntimeBindings) with type aliases from
  internal/runtime. Delegate all context helper functions to runtime.

- internal/ior.go, internal/ior_bpfsetup.go: remove imports of
  internal/tui and internal/tui/eventstream; use internal/runtime and
  internal/streamrow instead. Add SetTUIRunners injection point so the
  concrete TUI runner functions are wired in by cmd/ior/main.go.

- cmd/ior/main.go: call internal.SetTUIRunners with the concrete TUI
  runner functions before internal.Run, completing the wiring without
  creating a cycle.

- Test files (internal/ior_mode_test.go, internal/bench_pipeline_test.go):
  updated to use runtime.* and streamrow.* types in place of tui.* and
  eventstream.* types.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/cmd/ior/main.go b/cmd/ior/main.go
index ebd3ef3..9c5bac1 100644
--- a/cmd/ior/main.go
+++ b/cmd/ior/main.go
@@ -7,6 +7,7 @@ import (
 
 	"ior/internal"
 	"ior/internal/flags"
+	"ior/internal/tui"
 )
 
 // main is the entry point for the application. It checks if the OS is Linux,
@@ -32,6 +33,15 @@ func main() {
 		return
 	}
 
+	// Wire the concrete TUI runner functions into the core internal package.
+	// This is the only place that imports both internal and internal/tui, which
+	// breaks the cycle: internal no longer imports internal/tui.
+	internal.SetTUIRunners(
+		tui.RunWithTraceStarterConfig,
+		tui.RunTestFlamesWithTraceStarterConfig,
+		tui.RunTestFlamesWithTraceStarterConfig, // same runner; starter differs (static vs live)
+	)
+
 	// Run the internal logic of the application.
 	if err := internal.Run(cfg); err != nil {
 		fmt.Printf("Failed to run: %v\n", err)