Fix private package name

[goccy]

If multiple proto files are specified as arguments to protoc at the same time, there is a possibility of processing the same message defined in different packages. In this case, using only the grpc.federation.private package name would cause a name collision, so we generate the package name using the original package name. Additionally, since having the same file name in the Resolver results would cause an error, we ensure uniqueness by using the file name.

PR Overview

This PR fixes package name collisions caused by using a common private package name by generating package names that include the original package name and by ensuring unique file names.

• Renames keys from "grpc.federation.private." to "grpc.federation.private.org.federation." (or with similar namespace adjustments) across multiple generated files.
• Updates mappings for various federation examples (validation, alias, async, oneof, literal, condition, map, autobind, multi‑user, error handler, code gen plugin, load, CEL plugin, custom resolver, multi‑service, timeout, simple, retry, and minimum) consistently to support the PR’s purpose.

Reviewed Changes

File	Description
_examples/12_validation/federation/federation_grpc_federation.pb.go	Updated package keys for custom handler and message arguments.
_examples/06_alias/federation/federation_grpc_federation.pb.go	Renamed keys to include the original package name.
_examples/05_async/federation/federation_grpc_federation.pb.go	Updated argument keys for various message types.
_examples/10_oneof/federation/federation_grpc_federation.pb.go	Adjusted key names for oneof-related arguments.
_examples/08_literal/federation/federation_grpc_federation.pb.go	Renamed literal argument keys.
_examples/14_condition/federation/federation_grpc_federation.pb.go	Updated condition-related argument mapping keys.
_examples/13_map/federation/federation_grpc_federation.pb.go	Updated mapping keys for list and post item arguments.
_examples/07_autobind/federation/federation_grpc_federation.pb.go	Renamed keys in the autobind example.
_examples/09_multi_user/federation/federation_grpc_federation.pb.go	Updated keys for multi‑user arguments.
_examples/17_error_handler/federation/federation_grpc_federation.pb.go	Renamed error handler-related argument keys.
_examples/16_code_gen_plugin/federation/federation_grpc_federation.pb.go	Renamed key in the code gen plugin mapping.
_examples/18_load/federation/federation_grpc_federation.pb.go	Updated key names in the load example.
_examples/15_cel_plugin/federation/federation_grpc_federation.pb.go	Renamed keys in the CEL plugin example.
_examples/03_custom_resolver/federation/federation_grpc_federation.pb.go	Updated custom resolver key names (including federation.v2dev variants).
_examples/11_multi_service/federation/federation_grpc_federation.pb.go	Updated keys for multi‑service federation.
_examples/11_multi_service/federation/other_grpc_federation.pb.go	Consistently renamed keys in the other service file.
_examples/04_timeout/federation/federation_grpc_federation.pb.go	Updated timeout example key names.
_examples/02_simple/federation/federation_grpc_federation.pb.go	Updated simple federation keys for core messages.
_examples/19_retry/federation/federation_grpc_federation.pb.go	Updated retry example mapping keys.
_examples/01_minimum/federation/federation_grpc_federation.pb.go	Renamed key in the minimum example.

Copilot reviewed 38 out of 38 changed files in this pull request and generated no comments.

[github-actions]

Code Metrics Report

	main (e841d01)	#276 (23922de)	+/-
Coverage	65.3%	65.3%	+0.0%
Code to Test Ratio	1:0.3	1:0.3	-0.1
Test Execution Time	6m50s	6m52s	+2s

Details

  |                     | main (e841d01) | #276 (23922de) |  +/-  |
  |---------------------|----------------|----------------|-------|
+ | Coverage            |          65.3% |          65.3% | +0.0% |
  |   Files             |             77 |             77 |     0 |
  |   Lines             |          13800 |          13803 |    +3 |
+ |   Covered           |           9017 |           9019 |    +2 |
- | Code to Test Ratio  |          1:0.3 |          1:0.3 |  -0.1 |
  |   Code              |          42407 |          42413 |    +6 |
  |   Test              |          15913 |          15913 |     0 |
- | Test Execution Time |          6m50s |          6m52s |   +2s |

Code coverage of files in pull request scope (82.1% → 82.1%)

Files	Coverage	+/-
resolver/file.go	86.4%	+0.2%
resolver/message.go	70.9%	0.0%
resolver/resolver.go	83.4%	-0.1%

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Reported by octocov