feat(settings): lead MCP Access with plugin install, demote raw MCP

Per operator: the plugin install should supersede the bare MCP connection in
Settings, since the plugin incorporates the MCP and adds the session-start hook
+ skills. The Claude Code tab now leads with /plugin marketplace add + install
(with a persisted marketplace-URL field and the base-URL/key/project-id prompts
spelled out), and the old 'claude mcp add' command moves into a collapsed
'Advanced: connect the MCP only' disclosure.

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

frontend/src/views/SettingsView.vue

@@ -137,6 +137,18 @@ const claudeCodeCommand = computed(() => {
   --header "Authorization: Bearer ${effectiveApiKey.value}"`;
 });
 
+// Plugin install — the recommended path. The Scribe plugin bundles the MCP
+// connection, a session-start hook that surfaces your rules, and the Scribe
+// process-skills. The marketplace is the Scribe app's own git repo; persisted
+// per-browser like the MCP fields above.
+const _MKT_KEY = 'plugin_marketplace_url';
+const pluginMarketplaceUrl = ref<string>(localStorage.getItem(_MKT_KEY) || '');
+watch(pluginMarketplaceUrl, (v) => localStorage.setItem(_MKT_KEY, (v || '').trim()));
+const pluginInstallCommands = computed(() => {
+  const mkt = (pluginMarketplaceUrl.value || '').trim() || '<your-scribe-repo>.git';
+  return `/plugin marketplace add ${mkt}\n/plugin install scribe@scribe-plugin`;
+});
+
 const mcpConfigSnippet = computed(() => JSON.stringify({
   mcpServers: {
     [effectiveMcpName.value]: {
@@ -1546,20 +1558,64 @@ function formatUserDate(iso: string): string {
         </div>
 
         <!-- Claude Code tab -->
-        <ol v-if="mcpClientTab === 'claude-code'">
-          <li>
-            Register the server with Claude Code:
-            <div class="mcp-code-row">
-              <pre class="mcp-code">{{ claudeCodeCommand }}</pre>
-              <button class="btn btn-secondary btn-sm" @click="copySnippet(claudeCodeCommand, 'cc-add')">
-                {{ copiedSnippetKey === 'cc-add' ? 'Copied' : 'Copy' }}
-              </button>
-            </div>
-          </li>
-          <li>
-            Verify the connection by running <code>/mcp</code> inside Claude Code — <code>{{ effectiveMcpName }}</code> should appear as connected.
-          </li>
-        </ol>
+        <div v-if="mcpClientTab === 'claude-code'">
+          <p class="settings-description">
+            <strong>Recommended — install the Scribe plugin.</strong> One install wires up the MCP
+            connection, a session-start hook that surfaces your rules, and the Scribe process-skills.
+          </p>
+          <label class="mcp-config-field">
+            <span class="mcp-config-label">Scribe plugin marketplace (git URL)</span>
+            <input
+              v-model="pluginMarketplaceUrl"
+              type="text"
+              placeholder="https://git.example.com/you/Scribe.git"
+              class="settings-input"
+              spellcheck="false"
+            />
+            <span class="mcp-hint">
+              The Scribe app's own git repo — it ships the plugin in lockstep with this instance.
+            </span>
+          </label>
+          <ol>
+            <li>
+              Add the marketplace and install the plugin:
+              <div class="mcp-code-row">
+                <pre class="mcp-code">{{ pluginInstallCommands }}</pre>
+                <button class="btn btn-secondary btn-sm" @click="copySnippet(pluginInstallCommands, 'plugin-install')">
+                  {{ copiedSnippetKey === 'plugin-install' ? 'Copied' : 'Copy' }}
+                </button>
+              </div>
+            </li>
+            <li>
+              When prompted, enter your <strong>Scribe base URL</strong> (<code>{{ origin }}</code>),
+              an <strong>API key</strong> (generate one above), and optionally a
+              <strong>project id</strong> to scope the session-start context.
+            </li>
+            <li>
+              Restart Claude Code — <code>/mcp</code> shows <code>scribe</code> connected and your
+              standing rules load at session start.
+            </li>
+          </ol>
+
+          <details class="mcp-advanced">
+            <summary>Advanced: connect the MCP only (no plugin)</summary>
+            <ol>
+              <li>
+                Register just the MCP server:
+                <div class="mcp-code-row">
+                  <pre class="mcp-code">{{ claudeCodeCommand }}</pre>
+                  <button class="btn btn-secondary btn-sm" @click="copySnippet(claudeCodeCommand, 'cc-add')">
+                    {{ copiedSnippetKey === 'cc-add' ? 'Copied' : 'Copy' }}
+                  </button>
+                </div>
+              </li>
+              <li>
+                Verify with <code>/mcp</code> — <code>{{ effectiveMcpName }}</code> should appear as connected.
+                You won't get the session-start rule push or the Scribe skills this way.
+              </li>
+            </ol>
+          </details>
+        </div>
 
         <!-- Claude Desktop tab -->
         <ol v-else-if="mcpClientTab === 'claude-desktop'">
@@ -3162,6 +3218,19 @@ function formatUserDate(iso: string): string {
 }
 .mcp-code-row .mcp-code { margin-top: 0; }
 .mcp-code-row .btn-sm { white-space: nowrap; }
+.mcp-advanced {
+  margin-top: 1.25rem;
+  border-top: 1px solid var(--color-border, rgba(255, 255, 255, 0.1));
+  padding-top: 0.75rem;
+}
+.mcp-advanced summary {
+  cursor: pointer;
+  font-size: 0.85rem;
+  opacity: 0.75;
+  user-select: none;
+}
+.mcp-advanced summary:hover { opacity: 1; }
+.mcp-advanced[open] summary { margin-bottom: 0.5rem; }
 .mcp-hint {
   margin-top: 0.5rem;
   font-size: 0.8rem;