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/server/src/api/types.ts

@@ -273,6 +273,8 @@ export interface ModelTestRequest {
   apiKey?: string;
   /** "Clear saved API key" is checked: the test does **not** fall back to the stored key (tests against the current draft). */
   clearApiKey?: boolean;
+  /** Speed-test mode: raises the probe's output cap (16 -> 64 tokens) so TTFT/TPS are measurable; costs a little more quota. */
+  speed?: boolean;
   /**
    * base URL (not secret; the frontend always sends the form's current value): a string
    * means use it, `null` means explicitly clear it (no fallback to the stored value),
@@ -283,10 +285,23 @@ export interface ModelTestRequest {
   clientType?: string;
 }
 
-/** Connectivity test result: carries round-trip latency when ok, and a reason on failure (truncated raw provider error). */
+/**
+ * Connectivity test result: carries round-trip latency when ok, and a reason on failure
+ * (truncated raw provider error). When streamed content was observed, also carries the
+ * time-to-first-token and, when usage was reported (completed streams), the output rate.
+ */
 export interface ModelTestResponse {
   ok: boolean;
   latencyMs?: number;
+  /** Time from request start to the first streamed content (thinking or text), ms. */
+  ttftMs?: number;
+  /**
+   * Output tokens per second over the streaming window (first content -> stream end), 1dp.
+   * Omitted unless the sample is large enough to mean anything: a reply of a few tokens is
+   * dominated by the final chunk's round trip, so the rate it yields tracks network jitter
+   * rather than the model. Callers render TTFT alone in that case.
+   */
+  tps?: number;
   message?: string;
 }
 
@@ -342,6 +357,8 @@ export interface AgentSummary {
   vaultKeyCount: number;
   /** Schedule count (number of .toml files under agent_state/schedule/, including invalid ones). */
   scheduleCount: number;
+  /** Installed Skill count (number of agent_state/skills/<name>/ directories with a SKILL.md). */
+  skillCount: number;
 }
 
 export interface AgentsResponse {
@@ -460,12 +477,12 @@ export interface DirListResponse {
 }
 
 export interface SessionCreateRequest {
-  /** Upstream id of the session's model (paired with provider); defaults to the Project's default Model. */
+  /** Upstream id of the session's model; always sent together with provider. Omit both for the Project's default Model. */
   modelId?: string;
   /**
-   * Provider group for `modelId`; when omitted, resolved via resolveModelRef semantics —
-   * modelId can only be resolved if it's globally unique by exact match in the config;
-   * 0 or multiple matches return 400.
+   * Provider group for `modelId`. A model reference is always a complete
+   * (provider, modelId) pair — the provider is never inferred, so sending one field
+   * without the other returns 400 instead of being resolved.
    */
   provider?: string;
   /** Any existing directory on the server; defaults to auto-creating a temporary Workspace. */
@@ -930,9 +947,9 @@ export interface ScheduleItem {
   /** Bound target Session; defaults to creating a new Session each time. */
   sessionId?: string;
   workspace?: string;
-  /** Model for new-Session mode (upstream id, paired with provider); defaults to the Project's default reference. */
+  /** Model for new-Session mode (upstream id, always paired with provider); absent means the Project's default reference. */
   modelId?: string;
-  /** Provider group for `modelId`; when omitted, resolved via resolveModelRef semantics (resolvable only on a unique match). */
+  /** Provider group for `modelId`; present exactly when `modelId` is — a model reference is always a pair. */
   provider?: string;
   status: ScheduleStatus;
   invalidReason?: string;
@@ -959,9 +976,12 @@ export interface ScheduleUpsertRequest {
   endAt?: string;
   sessionId?: string;
   workspace?: string;
-  /** Model for new-Session mode (upstream id); defaults to the Project's default reference. */
+  /** Model for new-Session mode (upstream id); always sent together with provider, omit both for the Project's default reference. */
   modelId?: string;
-  /** Provider group for `modelId`; when omitted, validated as uniquely resolvable via resolveModelRef semantics at save/reconciliation time. */
+  /**
+   * Provider group for `modelId`. Both fields are sent as a pair (400 otherwise); the
+   * pair is checked against the Project config at save/reconciliation time.
+   */
   provider?: string;
 }