feat(ui): declutter dashboard done-recently + MCP-access, add per-project stats

Dashboard:
- 'Done recently' chip-cloud -> compact uniform list (Active-now row style),
  showing 5 with inline expand to the rest (backend already returns up to 8).
- New 'Projects' rail card: each active project with 'N open · M done'.
  Backend already computed done_count (dashboard.py) — now surfaced in the
  /api/dashboard payload per active project.

MCP Access (Connect Claude / Claude Code):
- Progressive disclosure: lead with the pre-filled plugin-install snippet;
  fold server name, scope, marketplace URL, and the MCP-only path into a
  single 'Customize' expander. Desktop tab keeps its own server-name field.
- Marketplace URL now defaults to this instance's own repo via
  config.PLUGIN_MARKETPLACE_URL (env-overridable); /api/plugin/marketplace-url
  falls back to it, so the field + install snippet are pre-filled out of the
  box instead of showing a generic placeholder.

Refs #761

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/scribe/config.py

@@ -38,6 +38,16 @@ class Config:
     BASE_URL: str = os.environ.get("BASE_URL", "http://localhost:5000").rstrip("/")
     TRUST_PROXY_HEADERS: bool = os.environ.get("TRUST_PROXY_HEADERS", "").lower() in ("1", "true", "yes")
 
+    # Git URL of the repo that ships this Scribe plugin. There is one correct
+    # value per deployment (the repo serving the plugin), so it's a config
+    # default — not something each user types. Surfaced in Settings → MCP Access
+    # as the default install-command marketplace; an admin can still override it
+    # per-instance via the Plugin marketplace setting.
+    PLUGIN_MARKETPLACE_URL: str = os.environ.get(
+        "PLUGIN_MARKETPLACE_URL",
+        "https://git.fabledsword.com/bvandeusen/FabledScribe.git",
+    )
+
     # OIDC / OAuth2 SSO (e.g. Authentik)
     OIDC_ISSUER: str = os.environ.get("OIDC_ISSUER", "")
     OIDC_CLIENT_ID: str = os.environ.get("OIDC_CLIENT_ID", "")