docs: add code quality and CI conventions to SDK docs (phase 2)

[TheRealAgentK]

Companion to the tooling repo Phase 2 PR. Adds content to SDK docs that was previously only in the tooling repo's checklist.

Changes

docs/manual/patterns.md (+71 lines)

• Code Quality Conventions: constants at module level, type hints, never hardcode credentials
• Linting and CI: ruff rules (E/F/W), per-file suppressions table, # noqa guidance, bandit config (B101 skipped), common bandit flags, pip-audit

docs/manual/building_your_first_integration.md (+11 lines)

• Platform OAuth test example showing wrapped auth structure alongside flat custom auth example

Related

• SDK Phase 1 PR: docs: unify integration documentation #13
• Tooling Phase 2 PR: docs: slim tooling docs, link to SDK (phase 2) autohive-integrations-tooling#16

[TheRealAgentK]

@Hamish-taylor @Shubhank-Jonnada @ProRedCat

This PR is essentially additions to the new SDK documentation we added in Phase 1 that came out of the cleanup of the tooling repo (which now had a lot of duplication).

[Shubhank-Jonnada]

lgtm!