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/skills/src/index.ts

@@ -139,34 +139,28 @@ export function loadLibrarySkills(): LibrarySkill[] {
  */
 export const SKILL_GROUPS: SkillGroupInfo[] = [
   {
-    id: "agent-development",
-    title: "Agent Development",
-    titleZh: "Agent 开发",
-    skills: ["agent-creation", "benchmark-design", "agent-evaluation", "agent-optimization"],
+    id: "office-productivity",
+    title: "Office Productivity",
+    titleZh: "办公效率",
+    skills: ["data-analysis", "firecrawl"],
   },
   {
-    id: "data-analysis",
-    title: "Data Analysis",
-    titleZh: "数据分析",
-    skills: ["data-analysis"],
+    id: "software-development",
+    title: "Software Development",
+    titleZh: "软件开发",
+    skills: ["web-design", "software-engineering"],
   },
   {
-    id: "penguin-development",
-    title: "Penguin Development",
-    titleZh: "Penguin 开发",
+    id: "ai-app-development",
+    title: "AI App Development",
+    titleZh: "AI 应用开发",
     skills: ["penguin-sdk", "penguin-cli", "agenthub-models"],
   },
   {
-    id: "web-development",
-    title: "Web Development",
-    titleZh: "网页开发",
-    skills: ["web-design"],
-  },
-  {
-    id: "software-engineering",
-    title: "Software Engineering",
-    titleZh: "软件工程",
-    skills: ["software-engineering"],
+    id: "agent-tuning",
+    title: "Agent Tuning",
+    titleZh: "Agent 调优",
+    skills: ["agent-creation", "benchmark-design", "agent-evaluation", "agent-optimization"],
   },
 ];