Move the start-task spec templates and the pr default template under .freethinking/ #36

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Kind

Change to a skill

Component

start-task (skill) and pr (skill)

Proposed behaviour

Apply the .freethinking/ override convention, which release 0.9.0 introduced for the report skill's four templates, to the two other sets of template files the plugin ships: skills/start-task/spec-template/ (requirements.md, design.md, tasks.md) and skills/pr/pull_request_template.md. Each skill reads .freethinking/<skill>/<file>.md at the repository root first and falls back to its own file, whole, never merged, saying in one line which was used, exactly as the README describes the convention. The README's "Tune the plugin for a repository" section drops the sentence "The spec templates of start-task and the default pull request template of pr are candidates to move there later" and lists the new files. pr keeps its existing precedence for the repository's own .github/pull_request_template.md; the override replaces only the skill's default.

Motivating case

The README and the description of PR #31 both name these files as the next candidates for the convention. Until they are covered, a repository that wants its own spec shape or its own default PR description has to fork the plugin, which is what .freethinking/ exists to avoid.