feat(rhdh-templates): add a new rhdh-templates skill for authoring and validating Software Templates in RHDH

[04kash]

Fixes: https://redhat.atlassian.net/browse/RHDHPLAN-1072

Summary

Adds rhdh-templates (v0.5.1): interactive authoring and validation for RHDH Software Templates. Stdlib-only Python CLIs, bundled examples (minimal-template, nodejs-backend, java-springboot), curated example catalog, JSON Schema validation, and optional live Scaffolder API integration via rhdh-local.

Reviewer quick check

uv sync --extra dev
uv run pytest tests/unit/test_rhdh_templates.py -v          # 39 tests, no RHDH needed
python skills/rhdh-templates/scripts/validate.py \
  --path skills/rhdh-templates/assets/examples/minimal-template --repo --json

Optional (live RHDH on :7007):

export RHDH_URL=http://localhost:7007 BACKSTAGE_TOKEN=development
uv run pytest tests/integration/test_rhdh_templates_live.py -v   # 4 tests, auto-skipped if unreachable

What's included

• skills/rhdh-templates/SKILL.md + 12 sub-command references
• Scripts: init, validate, fix_gotchas, analyze, create_location, list_examples, list_actions, explain_action, dry_run, schema_validate
• Parent routing update in skills/rhdh/SKILL.md

Test results

Suite	Count	Result	Notes
Unit	39	✅ pass	CI-safe; SKILL.md, references, bundled examples, all scripts
Integration (live)	4	✅ pass	Against rhdh-local baseline; skipped without RHDH_URL
Manual lab (phases 0–5)	4 templates	✅ pass	init → nodejs copy → templatize → java copy → live dry-run

Manual lab — template matrix

Template	Phase	Local validate	Live dry-run
example-template	init	✅ 0 critical	✅
my-node-api	nodejs copy	✅ 0 critical	✅
acme-widget-api	templatize	✅ 0 critical (2 warnings)	✅
my-spring-service	java copy	✅ 0 critical	✅

Phase 5 exercised list_actions, explain_action, and dry_run on all four templates. Integration pytest: 4 passed in 0.45s.

Known sharp edge

fix_gotchas --apply corrupted my-node-api/template.yaml during lab testing; restored from bundled example. Dry-run mode is safe — prefer it until apply behavior is hardened.

Test plan

• Unit tests (39/39)
• Bundled examples: zero critical findings on local validate
• Live integration tests (4/4) against rhdh-local
• End-to-end manual lab (phases 0–5)
• Reviewer: run unit tests + one validate.py --repo smoke check
• Reviewer (optional): live dry-run with RHDH_URL set