feat(coach): metric tables and show_result for the chat tools

get_metric_table reads one metric as days, weeks or months through the
chart reader, cut in the user's zone and collapsed to one source per day,
with null for a period without a reading. The model reads a bounded
summary; the full table rides the turn, encrypted at rest. show_result
shows a table an earlier reply of the same conversation fetched, resolved
only against that conversation's own messages. Workouts, labs, sleep and
adherence results project into tables, earlier tables are named in the
context by metadata alone, and result:rN marks are stripped from the reply.

docs/api/openapi.yaml

@@ -50490,6 +50490,7 @@ components:
             - get_workouts
             - get_cycle
             - get_correlations
+            - get_metric_table
             - show_result
             - snapshot
         labelKey:
@@ -50685,6 +50686,7 @@ components:
                 - get_workouts
                 - get_cycle
                 - get_correlations
+                - get_metric_table
             domain:
               $ref: "#/components/schemas/CoachStepDomain"
             window:
@@ -50977,6 +50979,7 @@ components:
                 - get_workouts
                 - get_cycle
                 - get_correlations
+                - get_metric_table
             domain:
               $ref: "#/components/schemas/CoachStepDomain"
             window: