Remove legacy spec loading strategy and obsolete spec files (#1417)

- Remove getTemplateData() legacy functions from gen_events_list.go and gen_resources_cmds.go
- Rename getTemplateDataFromUnifiedSpec to getTemplateData
- Delete obsolete spec files: spec3.sdk.json, spec3.v2.sdk.json, spec3.v2.sdk.preview.json
- Delete ZOOLANDER_SHA and sync-openapi-v2.sh script
- Remove update-openapi-spec and resource Makefile targets
- Update spec_test.go to use spec3.cli.json
- Update ARCHITECTURE.md documentation

Committed-By-Agent: cursor

Author: mikaelmello

ARCHITECTURE.md

@@ -14,7 +14,7 @@ The CLI uses the [Cobra library](https://github.com/spf13/cobra) for command str
 
 In addition to the handwritten commands, the CLI also has many auto-generated resources that correspond to base [API resources](https://stripe.com/docs/api/charges). These commands are registered in `pkg/cmd/resources_cmds.go`, calling the generic `NewNamespaceCmd` function for each resource. These auto-generated commands hold no functionality on their own and mostly rely on [operation commands](#operation-commands) to do anything (see below).
 
-The big list of commands found in `resources_cmds.go` is _itself_ an auto-generated file. It's built by running `pkg/gen/gen_resource_cmds.go`, which gets a big list of resources from OpenAPI via `api/openapi-spec/spec3.sdk.json` and generates the big command file via the `pkg/gen/resources_cmds.go.tpl` template. Generated commands can be manually overridden, as we do with `pkg/cmd/resource/events.go` taking precedence over the generated `events` command.
+The big list of commands found in `resources_cmds.go` is _itself_ an auto-generated file. It's built by running `pkg/gen/gen_resource_cmds.go`, which gets a big list of resources from OpenAPI via `api/openapi-spec/spec3.cli.json` and generates the big command file via the `pkg/gen/resources_cmds.go.tpl` template. Generated commands can be manually overridden, as we do with `pkg/cmd/resource/events.go` taking precedence over the generated `events` command.
 
 ### Operation Commands
 

Makefile

@@ -91,12 +91,6 @@ todo:
 		-nRo -E ' TODO:.*|SkipNow' .
 .PHONY: todo
 
-# Updates the OpenAPI spec
-update-openapi-spec:
-	rm -f ./api/openapi-spec/spec3.sdk.json
-	wget https://raw.githubusercontent.com/stripe/openapi/master/openapi/spec3.sdk.json -P ./api/openapi-spec
-.PHONY: update-openapi-spec
-
 # Releases a new version
 release:
 # This does not release anything from your local machine but creates a tag
@@ -162,9 +156,4 @@ protoc-gen-plugin:
 	@echo "Successfully compiled proto files for plugins"
 .PHONY: protoc-plugin
 
-resource:
-	./scripts/sync-openapi-v2.sh
-	@echo "✨ Successfully built Stripe CLI with latest API resources."
-.PHONY: resource
-
 .DEFAULT_GOAL := build