Add selected-plugin precedence and attribution to the MCP catalog (#27884)

## Why

**In short:** this PR resolves already-discovered MCP registrations. It
does not read selected plugins or discover their MCP servers.

The resolved MCP catalog currently builds config and auto-discovered
plugin registrations before runtime contributors are applied. A
thread-selected plugin needs a distinct precedence tier in that same
initial resolution pass: otherwise a disabled lower-precedence winner
can leave stale name-level state behind, and the winning MCP tools
cannot be attributed to the selected package reliably.

This PR adds that catalog boundary before executor discovery is
connected.

## What changed

- Added an explicit selected-plugin registration tier between
auto-discovered plugins and explicit config.
- Collected selected-plugin contributions before the initial catalog
build, while leaving compatibility and generic extension overlays in
their existing runtime phase.
- Retained the winning plugin ID and display name directly on
plugin-owned catalog registrations.
- Derived MCP tool provenance from the winning catalog entry instead of
joining against local-only plugin summaries.
- Retained the winning selected server's tool approval policy in the
running connection manager, so a selected registration cannot inherit
approval behavior from a losing local plugin.
- Kept remembered approval session-scoped for selected plugins until
there is an authority-aware persistence contract; Codex will not write
approval back to an unrelated local plugin.
- Preserved existing name-level disabled vetoes for discovered plugins
and config, while keeping a selected package's own disabled registration
scoped to that registration.
- Preserved deterministic selection order and existing config,
compatibility, and extension precedence.

The resulting order is:

```text
auto-discovered plugin
  < selected plugin
  < explicit config
  < compatibility registration
  < extension overlay
```

## Behavior and scope

This is a catalog and provenance change only. No production host
contributes selected-plugin MCP registrations yet, so existing local MCP
behavior remains unchanged.

The stacked follow-up, #27870, installs the executor plugin provider
that produces these registrations. App-server activation remains a
separate final step.

## Verification

Focused tests cover precedence, deterministic selected-plugin conflicts,
disabled-veto behavior across catalog phases, managed requirements
before selected-plugin resolution, winning-server approval policy, and
attribution when local and selected packages share an ID or server name.
CI owns execution of the test suite.

codex-rs/codex-mcp/src/mcp/mod.rs

@@ -12,6 +12,7 @@ pub use auth::should_retry_without_scopes;
 pub(crate) mod auth;
 
 use std::collections::HashMap;
+use std::collections::HashSet;
 use std::env;
 use std::path::PathBuf;
 use std::time::Duration;
@@ -141,7 +142,8 @@ pub struct McpConfig {
     pub client_elicitation_capability: ElicitationCapability,
     /// Resolved MCP registrations keyed by logical server name.
     pub mcp_server_catalog: ResolvedMcpCatalog,
-    /// Plugin metadata used to attribute MCP tools/connectors to plugin display names.
+    /// Plugin metadata used to attribute connector tools to plugin display names.
+    /// MCP registrations retain their own package attribution in the catalog.
     pub plugin_capability_summaries: Vec<PluginCapabilitySummary>,
 }
 
@@ -150,6 +152,7 @@ pub struct ToolPluginProvenance {
     plugin_display_names_by_connector_id: HashMap<String, Vec<String>>,
     plugin_display_names_by_mcp_server_name: HashMap<String, Vec<String>>,
     plugin_ids_by_mcp_server_name: HashMap<String, String>,
+    selected_plugin_mcp_server_names: HashSet<String>,
 }
 
 impl ToolPluginProvenance {
@@ -173,9 +176,12 @@ impl ToolPluginProvenance {
             .map(String::as_str)
     }
 
+    pub(crate) fn is_selected_plugin_mcp_server(&self, server_name: &str) -> bool {
+        self.selected_plugin_mcp_server_names.contains(server_name)
+    }
+
     fn from_config(config: &McpConfig) -> Self {
         let mut tool_plugin_provenance = Self::default();
-        let plugin_ids_by_mcp_server_name = config.mcp_server_catalog.plugin_ids_by_server_name();
         for plugin in &config.plugin_capability_summaries {
             for connector_id in &plugin.app_connector_ids {
                 tool_plugin_provenance
@@ -184,18 +190,31 @@ impl ToolPluginProvenance {
                     .or_default()
                     .push(plugin.display_name.clone());
             }
-
-            for server_name in plugin.mcp_server_names.iter().filter(|server_name| {
-                plugin_ids_by_mcp_server_name.get(*server_name) == Some(&plugin.config_name)
-            }) {
-                tool_plugin_provenance
-                    .plugin_display_names_by_mcp_server_name
-                    .entry(server_name.clone())
-                    .or_default()
-                    .push(plugin.display_name.clone());
-            }
         }
 
+        for (server_name, attribution) in config
+            .mcp_server_catalog
+            .plugin_attributions_by_server_name()
+        {
+            tool_plugin_provenance
+                .plugin_display_names_by_mcp_server_name
+                .insert(
+                    server_name.clone(),
+                    vec![attribution.display_name().to_string()],
+                );
+            tool_plugin_provenance
+                .plugin_ids_by_mcp_server_name
+                .insert(server_name, attribution.plugin_id().to_string());
+        }
+        tool_plugin_provenance
+            .selected_plugin_mcp_server_names
+            .extend(
+                config
+                    .mcp_server_catalog
+                    .selected_plugin_server_names()
+                    .map(str::to_string),
+            );
+
         for plugin_names in tool_plugin_provenance
             .plugin_display_names_by_connector_id
             .values_mut()
@@ -208,8 +227,6 @@ impl ToolPluginProvenance {
             plugin_names.sort_unstable();
             plugin_names.dedup();
         }
-        tool_plugin_provenance.plugin_ids_by_mcp_server_name = plugin_ids_by_mcp_server_name;
-
         tool_plugin_provenance
     }
 }