chore(copilot): remove duplicate skill

Author: serghei-dev

.github/agents/impl-pipeline.agent.md

@@ -100,7 +100,7 @@ Then assess:
 Delegate to the **Tester** subagent. Your prompt to the Tester must include:
 
 1. The Coder's implementation summary - quoted **verbatim**
-2. The instruction to load and follow the `go-testing` skill
+2. The instruction to load and follow the `test-go` skill
 3. The instruction to study the relevant spec sections and the actual implementation source files
 4. The instruction to apply the Analyze Protocol (3 YES criteria) before writing any test
 5. The instruction to verify with `make build`, `make test`, and `make lint`, and to **return the final exit status of each command** in the subagent result on its own labeled line (e.g., `build=pass`, `test=pass`, `lint=pass`). The orchestrator parses these lines directly into the Phase 4 summary; it does NOT re-run the commands.

.github/agents/tester.agent.md

@@ -29,7 +29,7 @@ You are the **Lead Go QA Engineer**. Write concise, resilient, and idiomatic tes
 
 ## Skill Requirement
 
-You MUST load and follow the `go-testing` skill before writing any test code. The skill contains the project's canonical test patterns, table-driven test structure, error assertion rules (`errors.As`/`errors.Is`), mock/fixture/httptest patterns, helper conventions, and a validation checklist. All generated tests must conform to the skill's guidelines. Do not write tests without first loading this skill.
+You MUST load and follow the `test-go` skill before writing any test code. The skill contains the project's canonical test patterns, table-driven test structure, error assertion rules (`errors.As`/`errors.Is`), mock/fixture/httptest patterns, helper conventions, and a validation checklist. All generated tests must conform to the skill's guidelines. Do not write tests without first loading this skill.
 
 ## Context
 

.github/prompts/test.prompt.md

@@ -7,16 +7,16 @@ agent: Tester
 
 I'm an Anthropic employee working on the Sortie project. Your task is to generate test coverage for the implemented feature or changed code.
 
-**MANDATORY:** Load and apply the `go-testing` skill before writing any test. The skill defines this project's canonical test patterns — table-driven structure, error assertions, mock patterns, fixture management, and validation checklist. All generated tests must conform to the skill's guidelines.
+**MANDATORY:** Load and apply the `test-go` skill before writing any test. The skill defines this project's canonical test patterns — table-driven structure, error assertions, mock patterns, fixture management, and validation checklist. All generated tests must conform to the skill's guidelines.
 
 ## Process
 
-1. **Load the `go-testing` skill** to obtain the project's test conventions and patterns.
+1. **Load the `test-go` Agent Skill** to obtain the project's test conventions and patterns.
 2. **Review the specification and implementation plan** (if provided) to understand the intended behavior and contracts.
 3. **Analyze the actual implementation** across all layers — read the source files before writing any tests.
 4. **Classify each test** by category: unit, unit with fixtures, unit with httptest, or integration (env-gated). Pick the lightest category that validates the behavior.
 5. **Identify what requires test coverage:** services, domain logic, state transitions, adapters, edge cases, regression risks, error paths, and concurrency safety.
-6. **Generate tests** following the `go-testing` skill conventions.
+6. **Generate tests** following the `test-go` skill conventions.
 7. **Verify** with `make test` — all tests must pass with `-race`.
 
 You MUST adhere to the following constraints: