docs: trim implementation detail from the OpenAPI/Swagger doc

mara, PR review: 'less impl details in user facing docs'. Dropped the
utoipa crate link, the ApiDoc source-file pointer, and the
#[utoipa::path(...)] annotation-syntax mention from the Dashboard
endpoints intro paragraph -- kept only what a reader needs (where to
find it, that it's a growing subset not yet the full list). Trimmed
the H0M3-page mention the same way.

docs/web-ui/dashboard.md

@@ -720,7 +720,10 @@ re-renders the terminal row. The root agent is addressed as `@root`.
 
 The H0M3 hub is the primary landing page (served at `/` by default). A
 responsive grid of link tiles — Dashboard, Flow, Logs, Matrix (when enabled),
-Forge (when enabled) — each pointing to their respective surfaces. The page
+Forge (when enabled), among others (Builds, Stats, Settings, Core,
+Credentials, API) — each pointing to their respective surfaces. The **API**
+tile always shows (unlike Matrix/Forge, see below) and links to the
+Swagger UI at `/api/docs`. The page
 is a pure portal with no tab-bar or SSE subscriptions. Typography + colours
 inherit from the shared theme (Catppuccin Mocha via `common.css` + `theme.css`).
 Optional tiles are hidden until `home.js` confirms their availability:
@@ -1148,6 +1151,11 @@ that's a browser-level decision, not ours.
 
 ## Dashboard endpoints
 
+Also browsable interactively at `/api/docs` (a Swagger UI, linked from
+the H0M3 hub's **API** tile), with the raw spec at `/api/openapi.json`.
+It's a growing supplement, not yet a full replacement for the list
+below — some endpoints aren't in it yet.
+
 - `POST /api/approve/{id}` — approve a pending approval. Fires
   `ApprovalResolved` on the dashboard event channel; client
   updates derived approvals state from the event.

frontend/packages/dashboard/src/index.html

@@ -100,6 +100,17 @@
         <span class="home-tile-desc">provision per-agent matrix + github accounts</span>
       </a>
 
+      <!-- API tile: no gating, unlike Forge/Matrix below — the OpenAPI
+           spec + Swagger UI are always served by hive-c0re itself
+           (docs/web-ui/dashboard.md::Dashboard endpoints). -->
+      <a class="home-tile" href="/api/docs">
+        <span class="home-tile-head">
+          <span class="home-tile-icon" aria-hidden="true">🧬</span>
+          <span class="home-tile-label">API</span>
+        </span>
+        <span class="home-tile-desc">interactive OpenAPI spec (Swagger UI)</span>
+      </a>
+
       <!-- Forge tile: hidden until home.js confirms the hive-forge
            container is up (state.forge_present); home.js also fills the
            href from state.forge_public_url (or the :3000 fallback), so