fix(server): cache health probes, surface SSE marshal errors, fail closed on missing duties

Health checks reuse a two-second snapshot and bound the schema query. Task SSE writes an error frame when an event cannot be encoded. ResolveDocTask errors when the frozen plan has no duty row, while explicit none-duties stay zero. Drop the unwired semantic-summary replace env, record the intentional dev versus release model split, document the test/main cutover path, and archive pre-goose SQL.

Co-authored-by: Cursor <cursoragent@cursor.com>

docker-compose.dev.yml

@@ -41,6 +41,7 @@ services:
       DATA_DIR: /app/data/workspaces
       MINIMAX_ENDPOINT_URL: ${MINIMAX_ENDPOINT_URL:-https://api.minimaxi.com/v1}
       MINIMAX_API_KEY: ${MINIMAX_API_KEY:-}
+      # dev iterates on highspeed; test/main pin MiniMax-M3. Do not align without a promotion decision.
       MINIMAX_MODEL_ID: ${MINIMAX_MODEL_ID:-MiniMax-M2.7-highspeed}
       MINIMAX_API_TYPE: ${MINIMAX_API_TYPE:-openai-compatible}
       MINIMAX_PROVIDER: minimax
@@ -114,9 +115,8 @@ services:
       MULTI_INTENT_U10_MUTATE: ${MULTI_INTENT_U10_MUTATE:-false}
       MULTI_INTENT_U11_DOCGOV: ${MULTI_INTENT_U11_DOCGOV:-false}
       MULTI_INTENT_U12_RUN_CONTROL: ${MULTI_INTENT_U12_RUN_CONTROL:-false}
-      # W2 PU6: shadow semantic summary; REPLACE stays unwired even if env is true
+      # W2 PU6: shadow semantic summary only. REPLACE stays unwired and is not declared here.
       SEMANTIC_SUMMARY_SHADOW: ${SEMANTIC_SUMMARY_SHADOW:-false}
-      SEMANTIC_SUMMARY_REPLACE: ${SEMANTIC_SUMMARY_REPLACE:-false}
       PI_CHANGE_REPORT_NARRATIVE: ${PI_CHANGE_REPORT_NARRATIVE:-false}
       # FAV U7: keep degraded read + in-process publisher off until separate approval
       FAV_DEGRADED_READ: ${FAV_DEGRADED_READ:-false}