fix(insights): backfill subscriptionTier from PostHog person props

inferSubscriptionTier only checked subscription_tier|tier|plan_tier|plan,
but Sase.tr's setPeopleProperties writes subscription_plan. Result: every
authed user showed tier=— in /insights/sessions/* and the tagger's
userValue boost (full=1.0, brand=0.7) collapsed to the 0.5 default.

- Add subscription_plan to the key list (priority first since it matches
  Sase.tr's actual property name)
- Extract into shared extractTierFromProps(props) helper
- In tag-sessions, re-evaluate tier from enrichment.userProperties and
  backfill when null. Tag step runs ~2min after ingest, by which point
  PostHog has the user's post-signup $set props that weren't on the
  recording row at ingest time.

apps/worker/src/jobs/tag-sessions.ts

@@ -1,7 +1,7 @@
 import { prisma } from "../db";
 import { tagSession, scoreSession } from "../lib/tagger";
 import { buildEnrichment } from "../lib/enrich";
-import { customEventPromoteReasons } from "../lib/heuristic";
+import { customEventPromoteReasons, extractTierFromProps } from "../lib/heuristic";
 import { getRecording } from "../lib/posthog";
 
 const MIN_SCORE_FOR_COMPRESSION = Number(process.env.INSIGHT_MIN_SCORE ?? "30");
@@ -56,6 +56,13 @@ export async function runTagSessions(): Promise<{ tagged: number; discarded: num
     const extraReasons = customEventPromoteReasons(eventNames);
     const mergedReasons = Array.from(new Set([...s.promotionReasons, ...extraReasons]));
 
+    // Backfill subscriptionTier from the re-fetched person properties.
+    // Ingest only sees properties that existed at recording-list time; the
+    // tag step runs later (cron@2min) by which point PostHog has the user's
+    // post-signup $set props. Don't overwrite an existing tier.
+    const inferredTier = extractTierFromProps(enrichment.userProperties);
+    const tierUpdate = !s.subscriptionTier && inferredTier ? { subscriptionTier: inferredTier } : {};
+
     const result = tagSession(s, enrichment);
     const score = scoreSession(s, result.severity, 0.5, 0.2, enrichment.groupProperties);
 
@@ -69,6 +76,7 @@ export async function runTagSessions(): Promise<{ tagged: number; discarded: num
           customEventCount: enrichment.customEvents.length,
           promotionReasons: mergedReasons,
           groupKey: enrichment.groupKey,
+          ...tierUpdate,
         },
       });
       discarded++;
@@ -86,6 +94,7 @@ export async function runTagSessions(): Promise<{ tagged: number; discarded: num
         customEventCount: enrichment.customEvents.length,
         promotionReasons: mergedReasons,
         groupKey: enrichment.groupKey,
+        ...tierUpdate,
       },
     });
     tagged++;

apps/worker/src/lib/heuristic.ts

@@ -65,9 +65,22 @@ export function inferAuthenticated(rec: PHRecordingListItem): boolean {
 }
 
 export function inferSubscriptionTier(rec: PHRecordingListItem): string | null {
-  const props = rec.person?.properties ?? {};
-  const v = props.subscription_tier ?? props.tier ?? props.plan_tier ?? props.plan;
-  return typeof v === "string" ? v : null;
+  return extractTierFromProps(rec.person?.properties ?? {});
+}
+
+// Shared between ingest (PostHog recording person props) and tag-step
+// (re-fetched person props via enrichment). Sase.tr sets `subscription_plan`
+// (and `subscription_status`, but status isn't a tier). Older code only
+// checked `subscription_tier`/`tier`/`plan_tier`/`plan`, missing the actual
+// property Sase.tr writes — so trial users showed up as tier=null forever.
+export function extractTierFromProps(props: Record<string, unknown>): string | null {
+  const v =
+    props.subscription_plan ??
+    props.subscription_tier ??
+    props.plan_tier ??
+    props.tier ??
+    props.plan;
+  return typeof v === "string" && v.length > 0 ? v : null;
 }
 
 // Promote signals derived from custom events (PRD v1.2 Bölüm 5.5).