Add planning documents for Phase 1 (throughput pipeline) and stub Phases 2-4

ROADMAP.md establishes status legend, architectural anchors pointing at the
wiki, and seven non-negotiable design rules — most importantly the
core/domain boundary that protects Phase 1 from Phase 2 churn, the
schema-authority split (positions hypertable owned here; everything else
owned by Directus), and idempotent-writes via (device_id, ts) ON CONFLICT.

Phase 1 (throughput pipeline) is fully detailed across 11 task files:
scaffold, core types + sentinel decoder, config + logging, Postgres
hypertable, Redis Stream consumer, per-device LRU state, batched writer,
main wiring, observability, integration test, Dockerfile + Gitea CI.
Observability is in Phase 1 (not deferred) — lesson learned from
tcp-ingestion task 1.10.

Phases 2-4 are stub READMEs. Phase 2 (domain logic) blocks on Directus
schema decisions and lists those open questions explicitly. Phase 3
(production hardening) and Phase 4 (future) sketch the task shape.

README.md

@@ -0,0 +1,7 @@
+# processor
+
+Node.js worker that consumes `Position` records from a Redis Stream (produced by `tcp-ingestion`), maintains per-device runtime state, applies racing-domain rules, and writes durable state to Postgres / TimescaleDB.
+
+For the architectural specification see [`../docs/wiki/entities/processor.md`](../docs/wiki/entities/processor.md). For the work plan and task status see [`.planning/ROADMAP.md`](./.planning/ROADMAP.md).
+
+This service is part of the [TRM](https://git.dev.microservices.al/trm) (Time Racing Management) platform.