Changelog, dev startup, README, AgentHub 0.4.0, model catalog, and landing site (#7)

Branch-length batch covering tooling, the model layer, the Web App and the public
surfaces. Highlights:

- Changelog: a per-release `changelog/<version>/` tree, grouped by the surface each
  change touches, with a root CHANGELOG.md holding one line per release.
- Dev startup: `scripts/dev-prebuild.mjs` serializes the skills+core prebuild behind a
  lock and keeps `pnpm install` current; `pnpm dev` runs server+web together.
- AgentHub 0.3.3 -> 0.4.0: OmniMessage complete payloads carry one opaque `fidelity`
  object in place of item-level `signature`/`phase`, threaded verbatim through Trace,
  replay and resume; malformed classification adapted to the new error types.
- Model layer: a model is always referenced by an explicit `(provider, model_id)` pair.
  The provider is never inferred, guessed or defaulted -- both the catalog inference and
  the unique-match config resolution are gone, and CLI, SDK, server routes and
  run_subagent all require the complete pair. Catalog gains the Qwen Token Plan, Qwen
  Pay-As-You-Go and Fireworks AI gateways, plus an expanded OpenRouter group.
- Web App: catalog preset sync and per-group speed test on the Models page, positional
  slash commands, a markdown renderer, skill-library update reminders, and a vertically
  centred draft page whose upward menus size themselves to the room available.
- Public surfaces: restructured READMEs, the penguin.ooo landing site and blog, refreshed
  benchmark results for both suites, and the demo videos playing on the landing page.

Includes the fixes from a full review of the branch: 23 confirmed findings, among them a
provider-inference bug that could send one vendor's API key to another vendor's endpoint,
and an Escape handler that destroyed the composer's contents unrecoverably.

Verified on the branch head: pnpm test (1127 passing, 7 packages), pnpm typecheck and
pnpm format:check clean, Playwright e2e 14/14.

packages/web/src/features/models/catalog-sync.ts

@@ -0,0 +1,74 @@
+/**
+ * One-click sync of the Project model table with the built-in catalog ("sync presets" next
+ * to the search box): union semantics — catalog entries not configured locally are added;
+ * entries present on both sides are reset to the catalog's fields (context window, pricing,
+ * protocol, base URL, vision — the catalog wins wherever the two differ, including removing
+ * pricing the catalog doesn't carry); locally added models (including user-defined groups)
+ * are kept untouched. Credentials are never touched: merged rows carry no apiKey input (the
+ * PUT keeps the stored key) and existing rows keep their credential display state.
+ */
+import { presetModelEntries } from "@prismshadow/penguin-core/model-catalog";
+import type { RowState } from "./models-page";
+
+type PresetEntry = ReturnType<typeof presetModelEntries>[number];
+
+/** The catalog-owned fields of a row, in RowState's string-typed form (mirrors toRow). */
+function presetFields(p: PresetEntry) {
+  return {
+    vision: p.vision !== false,
+    contextWindow: p.context_window !== undefined ? String(p.context_window) : "",
+    clientType: p.client_type ?? "",
+    cacheRead: p.pricing ? String(p.pricing.cache_read) : "",
+    cacheWrite: p.pricing ? String(p.pricing.cache_write) : "",
+    output: p.pricing ? String(p.pricing.output) : "",
+    baseUrl: p.base_url ?? "",
+  };
+}
+
+/** A brand-new row for a catalog entry not configured locally (original: null -> added on PUT). */
+function presetToRow(p: PresetEntry): RowState {
+  return {
+    provider: p.provider,
+    modelId: p.model_id,
+    original: null,
+    ...presetFields(p),
+    originalBaseUrl: "",
+    apiKeyInput: "",
+    clearApiKey: false,
+  };
+}
+
+/**
+ * Merges the current rows with the built-in catalog. Existing rows keep their identity,
+ * credential state, and list position (fields are updated in place); catalog-only entries
+ * are appended in catalog order. Returns the merged rows plus added/updated counts for the
+ * success toast (updated counts only rows whose catalog-owned fields actually changed).
+ */
+export function syncRowsWithCatalog(
+  rows: RowState[],
+  preset: PresetEntry[] = presetModelEntries(),
+): { rows: RowState[]; added: number; updated: number } {
+  const key = (provider: string, modelId: string) => `${provider}\0${modelId}`;
+  const index = new Map(rows.map((r, i) => [key(r.provider, r.modelId), i]));
+  const next = [...rows];
+  let added = 0;
+  let updated = 0;
+  for (const p of preset) {
+    const i = index.get(key(p.provider, p.model_id));
+    if (i === undefined) {
+      next.push(presetToRow(p));
+      added += 1;
+      continue;
+    }
+    const row = next[i]!;
+    const fields = presetFields(p);
+    const changed = (Object.keys(fields) as (keyof typeof fields)[]).some(
+      (k) => row[k] !== fields[k],
+    );
+    if (changed) {
+      next[i] = { ...row, ...fields };
+      updated += 1;
+    }
+  }
+  return { rows: next, added, updated };
+}