feat: Fallback to an alternate string if operationId is undefined.

[Himenon]

Summary

It will allow code to be generated even for schemas like the following.

  /undefined/operation/:id:
    get:
      # operationId: getUndefinedOperation
      responses:
        200:
          description: 成功
          content:
            application/json:
              schema:
                type: object
                properties:
                  message:
                    type: string
                    description: Undefined operation response

Test Plan

Updated snapshot test

[Copilot]

Pull Request Overview

This PR adds fallback operationId generation for OpenAPI operations missing an operationId, updates the core generator to apply this mapping, and refreshes tests/snapshots accordingly.

• Introduces generateValidRootSchema to assign synthetic operationIds based on method and path
• Integrates the fallback logic into src/index.ts before code generation
• Updates YAML fixture and Jest snapshots to reflect new operations and updated snapshot header URL

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/api.v2.domain/index.yml	Added a path without an explicit operationId
test/tests/functional/__snapshots/typedef-with-template-test.ts.snap	Updated snapshot header URL and added generated types for the new operation
test/tests/class/__snapshots/typedef-with-template-test.ts.snap	Same snapshot updates for the class-based client
src/index.ts	Imported and applied generateValidRootSchema
src/generateValidRootSchema.ts	New utility to assign fallback operationId values

Comments suppressed due to low confidence (2)

src/generateValidRootSchema.ts:7

• [nitpick] Rephrase the comment to follow project comment conventions and be more descriptive, e.g., Assign fallback operationId for operations without one.

  /** update undefined operation id */

src/generateValidRootSchema.ts:28

• The fallback operationId uses raw path characters (slashes, colons), which leads to generated names with $ tokens. Consider sanitizing the path—replacing non-alphanumeric characters with separators or underscores—to produce cleaner, more consistent operationId values.

        operation.operationId = `${method.toLowerCase()}${path.charAt(0).toUpperCase() + path.slice(1)}`;