Remove unused pipeline run coordinator

docs/internal/app.md

@@ -5,7 +5,7 @@
 `internal/app` owns the top-level application use cases. It coordinates
 configuration loading, secret resolution, backend construction, source bundle
 discovery, destination selection, publish planning, publish execution,
-notification handoff, run reporting, and in-memory run coordination.
+notification handoff, run reporting, and upload coordination.
 
 The package is the boundary between callers and lower-level domain packages. It
 does not own manifest validation rules, destination state comparison, storage
@@ -152,23 +152,6 @@ Oversized uploads, unsupported content types, invalid bearer tokens, full
 queues, and unknown status records are mapped to stable HTTP status codes
 without returning secret token values.
 
-## Coordination
-
-`PipelineRunCoordinator` wraps `RunPipeline` with in-memory admission control.
-It allows different pipeline IDs to run concurrently and rejects a second active
-run for the same pipeline ID.
-
-Coordinator records contain a run ID, pipeline ID, status, timestamps, completed
-report, and error text when applicable. Active state is memory-only and is
-cleared after success, failure, unknown pipeline ID, or context cancellation.
-
-The admission context is checked before a run is accepted. Once accepted, the
-run uses the coordinator lifetime context, so caller cancellation can stop
-waiting for admission without owning the actual run lifetime.
-
-The coordinator does not queue duplicate runs, persist run records, or define
-transport endpoints.
-
 ## Errors
 
 `Run` returns immediately for config loading errors, context cancellation before
@@ -187,10 +170,6 @@ aggregated into one run error after remaining destinations have been attempted.
 Destination diagnostics include pipeline ID, destination ID, backend, and
 bundle path.
 
-`PipelineRunCoordinator` returns `DuplicatePipelineRunError` when the same
-pipeline already has an active run. Callers can detect that condition with
-`IsDuplicatePipelineRun`.
-
 Stdout write errors are returned immediately because the caller's requested
 output stream can no longer be trusted.
 
@@ -211,7 +190,6 @@ Run helpers are grouped by responsibility:
 - `run_selection.go`: destination bundle selection, path mapping decisions, and fixed-path warnings.
 - `run_warnings.go`: secret and SSH warning records.
 - `run_notify.go`: notification event projection and action filtering.
-- `run_coordinator.go`: in-memory run admission, run IDs, status records, and duplicate-run errors.
 - `upload_coordinator.go`: in-memory upload admission, queue reservation, staging handoff, status tracking, queueing, and staged-source execution.
 - `upload_http.go`: HTTP upload authentication, routes, JSON response projection, and HTTP error mapping.
 - `serve.go`: HTTP server startup.
@@ -249,8 +227,8 @@ Before changing app orchestration, inspect tests under:
 - `internal/publish`
 
 Use focused app tests for report structure, single-pipeline execution,
-coordinator admission, warning generation, notification behavior, and
-partial-result aggregation.
+upload admission, warning generation, notification behavior, and partial-result
+aggregation.
 
 ## Invariants
 
@@ -259,7 +237,5 @@ partial-result aggregation.
 - Destination-scoped failures still produce a structured report plus an aggregated error.
 - Dry-run must not mutate destination storage or invoke notifications.
 - `RunPipeline` must use the same run path as `Run` after pipeline selection.
-- Duplicate in-flight runs are rejected only for the same pipeline ID.
-- Different pipeline IDs may run concurrently.
 - Concrete backend and transform registration stays at the app layer.
 - The default notifier is `notify.Noop`.