chore(cost-insights): drop the cost_insight_* tables and schema

CONTEXT.md

@@ -15,7 +15,6 @@ Covered domains must use this contract's canonical terms in code, docs, task des
 | **Security Sync** | Dependabot synchronization, finding persistence, notification eligibility, recipient intent materialization, and durable notification state | `services/security-sync/` | Event state remains owner-scoped; email sending does not occur inside finding persistence transactions |
 | **Security Agent Email Delivery** | Dispatch-time revalidation, email rendering, owner-aware links, and Mailgun delivery | `apps/web/src/app/api/internal/security-agent/`, `apps/web/src/lib/email.ts`, `apps/web/src/emails/` | Accepts notification identity only and loads current data before sending |
 | **Shared Security Notification Policy** | Canonical config parsing, defaults, severity thresholds, and pure event eligibility rules | `packages/worker-utils/src/security-notification-policy.ts` | Web and Worker must use same policy contract |
-| **Cost Insights** | Retired. No owned behaviour remains | `apps/web/src/components/cost-insights/CostInsightsDiscontinuedNotice.tsx` | Only the discontinued-notice routes remain; the unused `cost_insight_*` tables are scheduled to be dropped |
 | **Auto Routing** | Efficient model-pool settings, shared benchmark profiles, and per-request model selection | `packages/auto-routing-contracts/`, `services/auto-routing/`, `services/auto-routing-benchmark/`, `apps/web/src/components/auto-routing/` | Personal and organization settings constrain the existing `kilo-auto/efficient` model |
 | **Kilo Pass for Organizations** | Organization-owned Kilo Pass agreements, term versions, purchased pass capacity, sub-org allocation, and pooled bonus unlock behavior | Organization billing, seats, credits, sub-orgs, and Kilo Pass org administration surfaces | Separate source of truth from personal Kilo Pass subscriptions |
 
@@ -154,7 +153,6 @@ Covered domains must use this contract's canonical terms in code, docs, task des
 - **Kilo Pass processing runs** use leased idempotent retries, metrics, and manual replay. Blocked window shows persistent subscription-page status and sends one deduplicated email to current parent organization owners and billing managers.
 - The product does not support creating new custom or manual agreements. Platform admins may maintain imported legacy agreements by setting paid-through intervals, designating manual processing, scheduling commercial transitions, issuing audited compensation, or manually retrying; each mutation records actor, reason, before/after values, and timestamp.
 - Organization subscription page supports initial direct-child distribution before first issuance, then separates current immutable issuance snapshot from next **Kilo Pass allocation plan** and effective date; it shows purchased, parent-default, direct-child allocated, paid-through, pending-cancellation, blocked, and overallocated state.
-- **Cost Insights is retired.** No Cost Insights code runs: the UI, tRPC procedures, cron sweeps, spend capture, evaluation, alerting, and rollup maintenance are all removed, and none may be reintroduced. The `cost_insight_*` tables still exist but are no longer read or written, and are scheduled to be dropped.
 - Credit spend paths record spend and usage only. They no longer maintain an hourly spend rollup, so spend recording no longer depends on Cost Insights availability.
 - The former Cost Insights routes serve a discontinued notice so old bookmarks and previously sent alert emails do not land on a 404.
 - A **Security Finding Activity Event** falls into a report period based on when Kilo recorded or applied it. External source timestamps are supporting evidence and do not determine report inclusion.

packages/db/src/migrations/0204_drop_cost_insight_tables.sql

@@ -0,0 +1,12 @@
+DROP TABLE "cost_insight_active_suggestions" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_evaluation_dirty_owners" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_events" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_hourly_sweep_checkpoints" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_notification_deliveries" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_owner_configs" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_owner_hour_driver_buckets" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_owner_hour_totals" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_owner_states" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_rollup_coverage" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_rollup_degraded_intervals" CASCADE;--> statement-breakpoint
+DROP TABLE "cost_insight_rollup_repairs" CASCADE;