Add producer attempt state machine

docs/internal/pipeline.md

@@ -151,6 +151,17 @@ or rejected attempt. Cancellation stops retries. Normalizer-specific retry
 directives consume this same budget and validate any final safe fallback through
 the normalizer chain.
 
+The artifact-neutral producer-attempt state machine owns that shared budget,
+attempt provenance, semantic-correction material, and terminal-policy
+selection. It accepts producer and complete-validation closures, so artifact
+materialization, cache handling, checkpoints, and debug output stay at the
+operation boundary. It distinguishes operational, structural, module-requested,
+and semantic retries. A semantic retry is available only for a valid latest
+`single_response_v1` candidate; a deterministic or no-model rejection instead
+settles the semantic policy immediately. Structural-output errors alone use the
+structural policy, and validation failure without rejection settles the
+validator-failure policy without regenerating the producer.
+
 After terminal lane work, the runner assembles manifest provenance, normalized
 artifacts, rejections, warnings, and an optional accepted chunk map. When an
 output policy selected evidence lanes, it decodes accepted serialized normalize

docs/roadmap/implementation.md

@@ -471,7 +471,7 @@ the producer candidate advances. Existing stage callers may still adapt the
 report through their old disposition path until the next stages. This stage is
 one Terra prompt.
 
-## Stage 10 — Implement The Generic Producer Attempt State Machine
+## Stage 10 — Implement The Generic Producer Attempt State Machine ✅
 
 ### Goal