Context-meter amendment: CONTEXT_LIMITS dies — pi's live catalog is the only limit source

Owner ruling (2026-09-23, amendment to 04e336d): no hardcoded fallback
exists anywhere. contextWindow(record, limits) resolves the denominator
ONLY from the live index (provider:id -> contextWindow straight from
pi's catalog); a model missing from it (historical session, package
update, failed fetch) reads limit null and the meter renders
usage-only — the honest-render precedent, never a fake window.

- src/core/prices.ts: the 1354-entry CONTEXT_LIMITS table (65KB) and its
  generation apparatus deleted; the fold returns limit: number | null.
  PRICES untouched (regen verified byte-identical via the reworked
  sync-pricing script).
- scripts/sync-pricing.ts: generates PRICES only; contextWindow leaves
  the priced map, the guard, and the template.
- The dock meter's owner-selected treatment: the activity feed carries
  the limit server-side. catalogContextLimits() (server/model-catalog.ts)
  builds the index over the same keyed providers the picker federates;
  activityFeed() joins it onto every running job (ActivityJob.contextLimit,
  null when the model is missing — the dock reads it off the feed, no
  client-side table, no regression while the UI's catalog-join chunk lands).
- components/activity-dock.tsx: toBlobs reads job.contextLimit (import
  of CONTEXT_LIMITS gone); stats-bar renders usage-only on null limit
  (mechanical interim — UI stream's join chunk follows).
- tests: usage.test.ts pins the no-fallback contract (index hit / absent
  / empty / missing-model -> null); activity-feed.test.ts pins the
  server join (catalog model -> 1048576, unknown -> null, no-usage ->
  null); render pins updated to the interim usage-only render.

src/server/model-catalog.ts

@@ -153,6 +153,25 @@ export function toModelDto(model: Model<Api>): ModelDto {
 	};
 }
 
+/** The live-limits index (context-meter amendment, owner 2026-09-23):
+ *  provider:id → contextWindow from pi's catalog, over the SAME keyed
+ *  providers the picker federates. The one source for every context
+ *  meter's denominator — the stats-bar join holds /api/models' copy,
+ *  and the activity feed (observability.ts) resolves job limits
+ *  server-side through this. No hardcoded fallback exists anywhere:
+ *  a model missing here reads limit-null (usage-only, honest render). */
+export function catalogContextLimits(): Map<string, number> {
+	const keyed = keyedProviderIds();
+	const index = new Map<string, number>();
+	for (const provider of piModels().getProviders()) {
+		if (!keyed.has(provider.id)) continue;
+		for (const model of piModels().getModels(provider.id)) {
+			index.set(`${provider.id}:${model.id}`, model.contextWindow);
+		}
+	}
+	return index;
+}
+
 /** The full picker payload: every model of every configured provider
  *  (sorted by provider then id — stable, diff-friendly) + the config
  *  defaults a settings-less chat runs + the background roles' resolved