Expose code-mode tools through globals (#14517)

Summary
- make all code-mode tools accessible as globals so callers only need
`tools.<name>`
- rename text/image helpers and key globals (store, load, ALL_TOOLS,
etc.) to reflect the new shared namespace
- update the JS bridge, runners, descriptions, router, and tests to
follow the new API

Testing
- Not run (not requested)

codex-rs/core/src/tools/parallel.rs

@@ -9,6 +9,7 @@ use tracing::Instrument;
 use tracing::instrument;
 use tracing::trace_span;
 
+use crate::client_common::tools::ToolSpec;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::error::CodexErr;
@@ -46,6 +47,10 @@ impl ToolCallRuntime {
         }
     }
 
+    pub(crate) fn find_spec(&self, tool_name: &str) -> Option<ToolSpec> {
+        self.router.find_spec(tool_name)
+    }
+
     #[instrument(level = "trace", skip_all)]
     pub(crate) fn handle_tool_call(
         self,