chore: add issue/PR templates, shared rules, CLAUDE.md

[GigaHierz]

What this adds

One-time pm-kit bootstrap — templates and repo docs only, no CI changes:

• .github/ISSUE_TEMPLATE/ — bug_report.yml, task.yml, user_story.yml, config.yml
• .github/PULL_REQUEST_TEMPLATE.md
• .claude/shared/ — engineering-rules.md, money-path-checklist.md, tester-mode-pattern.md (synced from pm-kit going forward)
• CLAUDE.md — repo-owned router: Mintlify structure, mint dev / mint broken-links workflow, docs.json navigation pointers, gotchas

What this does NOT do

• No new CI. The repo keeps docs-validation.yml as its validation workflow; the pm-kit CI caller was intentionally not added.
• No existing file was modified or overwritten. renovate.json already existed and was left untouched.

Notes

• This repo has a CODEOWNERS file — changes under .github/ may require review from the listed owners.
• Branch protection: the required check name for this repo is Check for broken links, not ci / ci.

🤖 Generated with Claude Code

[palango]

Claude.md needs a merge, we should probably symlink that instead of referring to the other.

[GigaHierz]

Closing as superseded — no remaining delta worth merging.

Everything this PR set out to add has already landed on main through the AGENTS.md work (#2269): the issue/PR templates, the shared rules under .claude/shared/, and the PR template are all present on main. The command/workflow notes this branch's CLAUDE.md carried (mint dev, mint broken-links, the internal-link and llms.txt conventions) are all covered by AGENTS.md there too.

The only thing left in the effective diff was a standalone CLAUDE.md that both conflicts with and duplicates main's design, where AGENTS.md is the single acceptance standard and CLAUDE.md is a one-line pointer to it. Taking this branch's version would reverse that decision, so there's nothing to merge.

Leaving the branch (GigaHierz/pm-kit-bootstrap) in place in case any prose is worth cherry-picking later. No follow-up issue needed — the work is already on main.