[codex] Improve quality gates and coverage

[svngoku]

Requirements

This PR addresses the recent uncommitted quality cleanup work and prepares it for review after local verification. The requested outcome was to review the changes, confirm they are correct, push the code, and open a PR with the right project knowledge captured for reviewers.

Context / Project Knowledge

• The repository treats documentation and quality gates as part of the source of truth.
• AGENTS.md requires scoped source changes, preservation of user work, and relevant gate execution before handoff.
• The local quality gate is make check, which runs Ruff linting, Ruff format check, mypy, pytest, and the golden-principles repository check.
• Beads (bd) is the project issue workflow, but the local git hooks skipped bead sync because bd is not installed on this PATH.

Changes

• Adds focused unit coverage for BasicAgent, context-engineering primitives, search orchestration, and specialized-agent helper behavior.
• Tightens typing around model utilities, MCP optional imports, tool serialization, and structured helper returns.
• Normalizes formatting across agent, tool, config, test, and documentation files.
• Updates docs/QUALITY_SCORE.md with current evidence for tests, typing, documentation, and remaining coverage gaps.
• Adds types-requests to the dev dependency set and lockfile for cleaner type checking.

Verification

Ran the full local quality gate before committing:

PATH="$HOME/.local/bin:/opt/homebrew/bin:$PATH" make check

Results:

• uv run ruff check agentic_internet tests: passed
• uv run ruff format --check agentic_internet tests: passed, 45 files already formatted
• uv run mypy agentic_internet: passed, 29 source files
• uv run pytest: 184 passed, 4 Pydantic deprecation warnings
• python3 .opencode/tools/golden_principles.py: passed

Additional review checks run before push:

• git diff --check: passed
• pytest --cov=agentic_internet --cov-report=term-missing: 184 passed, total coverage 48%

Known Follow-Up

• multi_model_serpapi.py remains large and under-covered at 33% coverage.
• CLI coverage remains low at roughly 20%.
• The project still emits Pydantic V2 class-based config deprecation warnings.
• bd should be installed or added to PATH so git hooks can sync beads during future commits and pushes.