feat(coach): lay down the reasoning, trail and memory contract

Add the shared contract the reasoning release builds on, with no change
to how a turn runs today.

- Schema: operator reasoning controls on app_settings (0376), the
  encrypted trail text on coach_messages (0377), and source,
  last_used_at and source_message_id on coach_facts (0378).
- Provider contract: CompletionParams.reasoning and onReasoning,
  CompletionResult.reasoning and providerState, AiMessage.providerState.
- Reasoning levels, thinking budgets and the background-job table in
  src/lib/ai/reasoning/levels.ts; coachPrefsJson.reasoning, absent
  meaning medium, salvaged field by field like every other pref.
- Stream: activity, memoryNote and planProposal frames, done.stop and
  done.withheldResults, result.interim, a compare chart kind, eight
  table refs, three more clarification kinds with an assumed choice,
  the change_assumption chip, and assumptions, activity, stop,
  memoryNote and planProposal on the provenance. Zod mirror, type
  parity and the native-client key rule cover every new frame.
- Chat request: memoryDecision and planDecision, parsed and not yet
  acted on.
- Stub contracts for the memory functions and the activity recorder,
  inert until their implementations land.
- Backup, restore and rotation carry the new columns; a fact's message
  reference is resolved against the restored messages like its
  conversation reference.
- Message keys for the trail, memory, plans, assumptions, replies,
  interim tables, comparison charts and reasoning settings in all seven
  locales, each reachable from a catalog and checked both ways.

src/components/insights/coach-panel/result-chart.tsx

@@ -122,6 +122,9 @@ export function CoachResultChart({
   if (spec.kind === "histogram") {
     return <HistogramChart result={result} spec={spec} label={label} />;
   }
+  // v1.41 — the contract is in place; no table carries this kind yet, and the
+  // table view stays available until the chart lands.
+  if (spec.kind === "compare") return null;
   if (spec.kind === "bar" && spec.orientation === "horizontal") {
     return (
       <CategoryBarChart