Phase 3a: Information service authoring tools

[gregoryfoster]

Goal

Add the authoring-tool surface to the Information service so Claude (or a human operator) can compose and validate Information Items + InfoSpecs end-to-end without touching the database or Watcher.

Per design § 6 (Tools-first authoring lives on the Information service):

• `fetch_and_render(url)` — returns rendered HTML + headers + screenshot
• `propose_selectors(url, description)` — ranked candidate selectors with extracted preview and stability score
• `preview_extraction(url, selector, options)` — what would be captured + computed fingerprint
• `validate_info_spec(doc)` — schema validation + dry-run extraction
• `create_info_spec(info_item_id, doc, priority)` — append a new InfoSpec to the priority list (immutable body, new ULID)
• `create_info_item(name, description, initial_info_spec_doc)` — register a new Information Item + first InfoSpec atomically
• `find_info_item(query)` — search to avoid duplicates

`create_info_item` and `create_info_spec` already exist (Phase 1); 3a extends `create_info_item` with the atomic `initial_info_spec` variant and adds the five missing tools.

Plan

docs/plans/2026-05-05-information-service-phase3a-plan.md

Out of scope

• Phase 3b (Archive service stand-up on port 8030) — separate plan.
• Screenshot in `fetch_and_render` (waits on Add Playwright headless browser fetcher #3 Playwright fetcher).
• Watcher-side authoring tools (`create_watch`, `test_watch`).
• Multi-selector InfoSpecs (Phase 2c follow-up: multi-selector InfoSpec extension #141), fetch_config knobs (Phase 2c follow-up: InfoSpec schema extension for fetch_config knobs #142), inline InfoItem creation from the Watch form (Phase 2c follow-up: inline InfoItem creation from the Watch form #140).

References

• Design doc: docs/plans/2026-05-03-information-source-specifications-design.md
• Predecessor: Information Source Specifications & Watcher boundary realignment #138 (closed)