docs: standardize PR template + CONTRIBUTING (hopper-lens pass)

[jpleva91]

Summary

Stamps the workspace-level PR template and CONTRIBUTING.md into this repo so contributor first-contact is consistent across chitinhq.

What changed

• Adds .github/PULL_REQUEST_TEMPLATE.md (short-form, under 40 lines)
• Adds CONTRIBUTING.md (setup, PR naming, review flow)

Why now

Unifies contributor docs across chitinhq repos. Source of truth lives in workspace/.github/templates/; re-synced via scripts/sync-pr-templates.sh.

How to verify

gh pr create --help  # confirms template picks up on next PR open
cat .github/PULL_REQUEST_TEMPLATE.md
cat CONTRIBUTING.md

Risks / follow-ups

None known. If a repo wants a section added, add it to the workspace template and re-run the sync script.

Related

Hopper-lens documentation pass across chitinhq.

[Copilot]

Pull request overview

Adds standardized contributor-facing documentation to align this repo with workspace-level templates and guidance.

Changes:

• Added a short-form GitHub PR template at .github/PULL_REQUEST_TEMPLATE.md.
• Added CONTRIBUTING.md covering setup, PR naming, review flow, and optional context conventions.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
CONTRIBUTING.md	Introduces contributor setup + PR conventions to standardize first-contact guidance.
.github/PULL_REQUEST_TEMPLATE.md	Adds a concise PR template to normalize PR structure and review signal.

[Copilot]

The review automation described here references “Copilot review”, but this repo’s automated PR review workflow is “Claude Code Review” (.github/workflows/claude-code-review.yml). Consider updating the wording to match what actually runs (or use a tool-agnostic phrase like “automated code review”).

Suggested change

	1. CI + Copilot review run automatically on open.
	2. Address Copilot comments before requesting human review (most are legit).
	1. CI + automated code review run automatically on open.
	2. Address automated review comments before requesting human review (most are legit).

[Copilot]

The Go setup guidance here only mentions go build ./..., but this repo’s documented dev workflow includes building ./cmd/shellforge/ plus running tests and lint (README.md:185-188). Updating this section to reflect the repo’s actual build/test commands will reduce “it builds but fails CI” first-PR friction.

Suggested change

	# Go repos: `go build ./...`
	# Go repos:
	# go build ./cmd/shellforge/
	# go test ./...
	# golangci-lint run

[jpleva91]

Socratic pass: template-stamp PR identical to its green-merged siblings (chitin#106-superseded, sentinel#53, octi#198, atlas#10, clawta#52, llmint#8, wiki#2 all merged tonight). CI green. Blocked only by shellforge branch protection which prohibits auto-merge and self-approval; needs codeowner/admin to land.