Consolidate future roadmap documentation

docs/roadmap/implementation.md

@@ -1,26 +0,0 @@
-# Producer Upload Implementation Roadmap
-
-The producer upload implementation described by this roadmap is complete.
-Current behavior is documented outside roadmap files:
-
-- [README](../../README.md)
-- [Source bundle contract](../integrations/source-bundle.md)
-- [HTTP upload contract](../integrations/http-upload.md)
-- [Operations](../operations.md)
-- [Troubleshooting](../troubleshooting.md)
-- [Application internals](../internal/app.md)
-- [Development policy](../policy/development.md)
-
-This file now tracks only producer-upload work that remains outside the current
-implementation.
-
-## Deferred Work
-
-- Durable idempotency storage across server restarts.
-- Database-backed queues or durable producer retry processing.
-- `UploadAndWait`, long polling, run cancellation, run retry, or run listing
-  helpers.
-- Zstandard archives.
-- Multipart, resumable, or streaming upload protocols.
-- URL-token authentication.
-- Browser UI or public exposure defaults.