feat: add UK Companies House handler skill (#172)

[Areen-09]

Description

This PR introduces the finance/uk_companies_house_handler skill (v1 scope). It provides deterministic operations to interface with the UK Companies House REST API.

Logic & Cognition Changes:

• Introduces deterministic parsers/mappers to turn agent intent (e.g. looking for a CEO) into structured API operations (search_companies, get_company_profile, list_officers).
• Implements an orchestration helper pattern where ambiguous queries return a needs_input status with candidate matches, forcing the agent to disambiguate before fetching detailed data (like officers or filings).
• All natural language understanding is handled by the host agent via instructions.md; the skill logic in skill.py is entirely deterministic Python and requests.

Documentation & Tests:

• Adds the full skill bundle (manifest.yaml, skill.py, instructions.md, card.json, test_skill.py).
• Adds catalog page docs/skills/uk_companies_house_handler.md (with usage examples for all 5 providers).
• Updates docs/skills/README.md and CHANGELOG.md.
• Bundle tests are implemented with fully mocked HTTP requests to ensure no live API calls run in CI.

Type of Change (Matches Issue Templates)

• Skill Proposal: New Skill (Contains manifest.yaml, skill.py, and instructions.md)
• Bug Report Fix: Non-breaking change which fixes an execution error or framework bug
• Doc Fix: Documentation Update
• Framework Feature / RFC Updates: Core Framework Update (Changes to base_skill.py, loader.py, etc.)

Checklist (all PRs)

• My code follows the Agent Code of Conduct.
• I have run python -m flake8 ., pytest skills/ (or skillware test), and pytest tests/ locally (or the subset relevant to this change).
• CHANGELOG.md updated under [Unreleased] if this PR changes user-visible behavior.
• examples/README.md is updated if this PR adds, renames, or removes a runnable script under examples/.

New or updated skill (complete only if this PR adds or changes a skill under skills/)

Skip this section for framework-only, documentation-only, or other PRs that do not touch the skill registry.

Bundle & metadata

• Skill lives at skills/<category>/<skill_name>/ (copied from templates/python_skill/ or equivalent).
• manifest.yaml has name, version, description, valid parameters, and constitution.
• manifest.yaml includes issuer with real name and email (not template placeholders).
• Optional: short_description in manifest (~80 chars) for skillware list.
• Optional: issuer.github and issuer.org set when applicable.
• requirements and env_vars are documented when the skill needs them.

Logic, cognition, and UI

• skill.py is deterministic Python (no arbitrary LLM-generated code paths).
• instructions.md explains when and how to use the skill.
• card.json is present and its issuer matches manifest.yaml (name and email at minimum).

Tests & loader

• test_skill.py covers execution and schema expectations.
• SkillLoader.load_skill("<category>/<skill_name>") succeeds (or missing deps are documented).

Documentation & catalog

• docs/skills/<skill_name>.md exists or is updated (ID, Issuer, usage).
• docs/skills/README.md lists the skill with ID and Issuer.

Constitution & Safety (if adding or modifying a skill)

• Read-Only: Uses only public Companies House data. No operations for filing or modifying company records are included.
• Privacy: Requires API key (COMPANIES_HOUSE_API_KEY) via environment variable. No caching of personal or company data beyond the lifecycle of the immediate request.
• Provenance: Always cites the company number and data timestamp in the returned payload.
• Disclaimer: Strictly acts as an information retrieval tool and is not a substitute for legal, accounting, or professional financial advice.

Related Issues

Implements v1 of #172

[rosspeili]

Thanks @Areen-09, this is a very strong v1 impl for #172.

Reviewed the bundle, docs, examples, and ran live Companies House calls (resolve_company, get_officers for BP P.L.C., map_intent), all worked with COMPANIES_HOUSE_API_KEY. CI scope passes locally (218 tests).

While this is merge-ready, I would include these minor hotfix in follow-ups pr:

• Consider enriching get_officers with company_name via profile when the officers endpoint omits it
• Maybe one-line mention of COMPANIES_HOUSE_API_KEY in docs/usage/api_keys.md, but not a blocker since it is already in .env.example

Nice work on the envelope, terminology map, and mocked test coverage, this follow the issue instructions cleanly <3 Merging.