fix: update GitHub Copilot's prompt files to replace deprecated 'mode' attribute with 'agent'

Author: irisTa56

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-design.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: 'Generate comprehensive technical design for a specification'
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-impl.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: 'Execute spec tasks using TDD methodology'
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-init.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Initialize a new specification with detailed project description
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-requirements.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Generate comprehensive requirements for a specification
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-status.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Show specification status and progress
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-spec-tasks.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Generate implementation tasks for a specification
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-steering-custom.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Create custom steering documents for specialized project contexts
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-steering.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Manage {{KIRO_DIR}}/steering/ as persistent project knowledge
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-validate-design.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Interactive technical design quality review and validation
 ---
 <meta>

tools/cc-sdd/templates/agents/github-copilot/commands/kiro-validate-gap.prompt.md

@@ -1,5 +1,5 @@
 ---
-mode: 'agent'
+agent: 'agent'
 description: Analyze implementation gap between requirements and existing codebase
 ---
 <meta>