Implement Collections feature for grouping related prompts, instructions, and chat modes (#232)

* Initial plan

* Implement core Collections feature with YAML parsing and README generation

Co-authored-by: aaronpowell <434140+aaronpowell@users.noreply.github.com>

* Complete Collections feature implementation with validation, tooling, and documentation

Co-authored-by: aaronpowell <434140+aaronpowell@users.noreply.github.com>

* Update generated README files to include collections instructions

* Fix YAML parsing logic bug: replace impossible condition with proper indentation check

Co-authored-by: aaronpowell <434140+aaronpowell@users.noreply.github.com>

* Refactor: Extract YAML parser to shared module and improve user experience

Co-authored-by: aaronpowell <434140+aaronpowell@users.noreply.github.com>

* fixing task and file permissions

* Better args handling

* Adding some more collections

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: aaronpowell <434140+aaronpowell@users.noreply.github.com>
Co-authored-by: Aaron Powell <me@aaron-powell.com>

collections/project-planning.collection.yml

@@ -0,0 +1,44 @@
+id: project-planning
+name: Project Planning & Management
+description: Tools and guidance for software project planning, feature breakdown, epic management, implementation planning, and task organization for development teams.
+tags: [planning, project-management, epic, feature, implementation, task, architecture]
+items:
+  # Planning Chat Modes
+  - path: chatmodes/task-planner.chatmode.md
+    kind: chat-mode
+  - path: chatmodes/task-researcher.chatmode.md
+    kind: chat-mode
+  - path: chatmodes/planner.chatmode.md
+    kind: chat-mode
+  - path: chatmodes/plan.chatmode.md
+    kind: chat-mode
+  - path: chatmodes/prd.chatmode.md
+    kind: chat-mode
+  - path: chatmodes/implementation-plan.chatmode.md
+    kind: chat-mode
+
+  # Planning Instructions
+  - path: instructions/task-implementation.instructions.md
+    kind: instruction
+  - path: instructions/spec-driven-workflow-v1.instructions.md
+    kind: instruction
+
+  # Planning Prompts
+  - path: prompts/breakdown-feature-implementation.prompt.md
+    kind: prompt
+  - path: prompts/breakdown-feature-prd.prompt.md
+    kind: prompt
+  - path: prompts/breakdown-epic-arch.prompt.md
+    kind: prompt
+  - path: prompts/breakdown-epic-pm.prompt.md
+    kind: prompt
+  - path: prompts/create-implementation-plan.prompt.md
+    kind: prompt
+  - path: prompts/update-implementation-plan.prompt.md
+    kind: prompt
+  - path: prompts/create-github-issues-feature-from-implementation-plan.prompt.md
+    kind: prompt
+
+display:
+  ordering: alpha
+  show_badge: true