feat(linkedin-studio): N7.5 — MR-F9 etterspørsels-sveip (Tier-5-kilder + smertepunkt + vokabular-oversettelse + arc-kontrakt) [skip-docs]

The «innenfra og ut» demand-sweep: the mechanism that FILLS the N6 reader fields
(readerQuestion/painPoint/saturation). Discovery finds "what happened"; this layer
translates it into "the problem the reader is stuck on".

- demand-spotter agent (agents 19->20, inherits session): three passes after
  discovery, before drafting — demand-sweep -> pain-point map -> vocabulary translation.
- Tier 5 demand sources in config/trends-sources.template.md (inverse of Tier 1-4;
  honest blind spots: YouTube API, Reddit approximate, HN/GitHub ground truth).
- demand signal on TrendRecord (strength + answered) — rankable twin of the verbatim
  saturation text; additive-optional, store schema stays v4 (no migration).
- arc.ts (§4 output contract): groupIntoArcs (relatedIds transitive closure),
  rankArcQuestions (etterspørsel x kan-svare x ikke-besvart), classifyMarketGap
  (supply-gap != demand-gap != saturated). Pure + deterministic (TDD).
- arcs CLI verb + /linkedin:trends --demand mode (commands stay 30); morning brief
  shows the per-candidate demand signal.

Suites: trends 276->300, test-runner 139->140, tsc clean. Others unchanged
(brain 134, hooks 140, tests 35, render 60).

MR-F9 built (bygget-men-ubevist) — the (a)/(b)/(c) evidence gate is a runtime
demonstration, proven consumer-side (plugin agents don't resolve in the dev repo).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014bE7VbkmR3cqHFEeGfzgwb

scripts/trends/src/brief.ts

@@ -280,6 +280,8 @@ function proposalLines(t: TrendRecord): string[] {
   if (t.readerQuestion) out.push(`- ❓ Leserspørsmål: ${t.readerQuestion}`);
   if (t.painPoint) out.push(`- 🩹 Smertepunkt: ${t.painPoint}`);
   if (t.saturation) out.push(`- 🌡️ Metning: ${t.saturation}`);
+  // N7.5 (MR-F9): the demand-sweep's rankable signal, shown alongside the verbatim saturation above.
+  if (t.demand) out.push(`- 📊 Etterspørsel: ${t.demand.strength} · besvart: ${t.demand.answered ? "ja" : "nei"}`);
   if (t.relatedIds && t.relatedIds.length > 0) out.push(`- ↔️ Relatert: ${t.relatedIds.join(", ")}`);
   return out;
 }