[codex] Improve built-in tool schema docs (#24794)

## Summary
- Clarify default, omission, and bounded behavior across built-in tool
schemas, including unified exec, classic shell, Code Mode exec/wait,
multi-agent, agent job, MCP resource, image, goal, plan, tool_search,
and test-sync fields.
- Convert update_plan status to an enum and add short field descriptions
where the schema previously relied on surrounding context.
- Remove the dedicated permission-approval schema test and keep only
updates to existing expected-spec tests.

## Validation
- Ran `just fmt`.
- Ran `git diff --check`.
- Did not run clippy or tests, per request.

Regression has been eval
[here](https://openai.slack.com/archives/C09GDSP1J9X/p1779905065496949)
and we proved there are no regressions

codex-rs/core/src/tools/code_mode/wait_spec.rs

@@ -12,20 +12,19 @@ pub(crate) fn create_wait_tool() -> ToolSpec {
         (
             "yield_time_ms".to_string(),
             JsonSchema::number(Some(
-                "How long to wait (in milliseconds) for more output before yielding again."
-                    .to_string(),
+                "Wait before yielding more output. Defaults to 10000 ms.".to_string(),
             )),
         ),
         (
             "max_tokens".to_string(),
             JsonSchema::number(Some(
-                "Maximum number of output tokens to return for this wait call.".to_string(),
+                "Output token budget for this wait call. Defaults to 10000 tokens.".to_string(),
             )),
         ),
         (
             "terminate".to_string(),
             JsonSchema::boolean(Some(
-                "Whether to terminate the running exec cell.".to_string(),
+                "True stops the running exec cell; false or omitted waits for output.".to_string(),
             )),
         ),
     ]);
@@ -77,20 +76,21 @@ mod tests {
                         (
                             "max_tokens".to_string(),
                             JsonSchema::number(Some(
-                                "Maximum number of output tokens to return for this wait call."
+                                "Output token budget for this wait call. Defaults to 10000 tokens."
                                     .to_string(),
                             )),
                         ),
                         (
                             "terminate".to_string(),
                             JsonSchema::boolean(Some(
-                                "Whether to terminate the running exec cell.".to_string(),
+                                "True stops the running exec cell; false or omitted waits for output."
+                                    .to_string(),
                             )),
                         ),
                         (
                             "yield_time_ms".to_string(),
                             JsonSchema::number(Some(
-                                "How long to wait (in milliseconds) for more output before yielding again."
+                                "Wait before yielding more output. Defaults to 10000 ms."
                                     .to_string(),
                             )),
                         ),