fix: wire after_tasks and after_implement hook events into command templates (#1702)

* fix: wire after_tasks and after_implement hook events into command templates (#1701)

The HookExecutor backend in extensions.py was fully implemented but
check_hooks_for_event() was never called by anything — the core command
templates had no instructions to check .specify/extensions.yml.

Add a final step to templates/commands/tasks.md (step 6, after_tasks) and
templates/commands/implement.md (step 10, after_implement) that instructs
the AI agent to:

- Read .specify/extensions.yml if it exists
- Filter hooks.{event} to enabled: true entries
- Evaluate any condition fields and skip non-matching hooks
- Output the RFC-specified hook message format, including
  EXECUTE_COMMAND: markers for mandatory (optional: false) hooks

Bumps version to 0.1.7.

* fix: clarify hook condition handling and add YAML error guidance in templates

- Replace ambiguous "evaluate any condition value" instruction with explicit
  guidance to skip hooks with non-empty conditions, deferring evaluation to
  HookExecutor
- Add instruction to skip hook checking silently if extensions.yml cannot
  be parsed or is invalid

* Fix/extension hooks not triggered (#1)

* feat(templates): implement before-hooks check as pre-execution phase

* test(hooks): create scenario for LLMs/Agents on hooks

---------

Co-authored-by: Dhilip <s.dhilipkumar@gmail.com>

tests/hooks/spec.md

@@ -0,0 +1 @@
+- **User Story 1:** I want a test script that prints "Hello hooks!".