Complete comprehensive Codex → LLMX branding update

Fixed all remaining user-facing "Codex" references across entire codebase:
- Updated all UI strings and error messages
- Fixed GitHub issue templates and workflows
- Updated MCP server tool descriptions and error messages
- Fixed all test messages and comments
- Updated documentation comments
- Changed auth keyring service name to "LLMX Auth"

Reduced from 201 occurrences to only code identifiers (struct/type names).
Changes span 78 files across Rust, Python, YAML, and JSON.

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

llmx-rs/mcp-types/generate_mcp_types.py

@@ -385,7 +385,7 @@ def define_struct(
         else:
             fields.append(StructField("pub", rs_prop.name, prop_type, rs_prop.serde, rs_prop.ts))
 
-    # Special-case: add Codex-specific user_agent to Implementation
+    # Special-case: add LLMX-specific user_agent to Implementation
     if name == "Implementation":
         fields.append(
             StructField(
@@ -394,7 +394,7 @@ def define_struct(
                 "Option<String>",
                 '#[serde(default, skip_serializing_if = "Option::is_none")]',
                 '#[ts(optional)]',
-                "This is an extra field that the Codex MCP server sends as part of InitializeResult.",
+                "This is an extra field that the LLMX MCP server sends as part of InitializeResult.",
             )
         )
 

llmx-rs/mcp-types/src/lib.rs

@@ -527,7 +527,7 @@ pub struct Implementation {
     #[ts(optional)]
     pub title: Option<String>,
     pub version: String,
-    // This is an extra field that the Codex MCP server sends as part of InitializeResult.
+    // This is an extra field that the LLMX MCP server sends as part of InitializeResult.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional)]
     pub user_agent: Option<String>,