Knowledge skills: project-structure, local-dev, testing, client-smoke #4872

Part of the agentic software factory tracker #4858, Wave 4. Proposed as S11 in docs/agent-guidance-inception.md (PR #4861) §9, from #4859.

Depends on

After Part 3 (skills infrastructure), which has landed. Nothing else blocks it.

testing documents the harnesses and test layout as they are today. It does not wait on #4854 and #4855: those issues update the skill when they change the harness design and add the per-file coverage gate.

Scope

Adapt from the Inspector (§6 of the doc):

• project-structure: each server's layout, and where a new file goes.
• local-dev: npm workspaces and uv; running each server over the transports it implements (stdio for all seven; everything also serves SSE and Streamable HTTP); local npx/uvx builds; pin with overrides, never npm audit fix.
• testing: in-process protocol harnesses (an SDK Client over an in-memory transport for TS; ClientSession for Python), test placement, and the test vs coverage commands. The per-file coverage gate is added to the skill by Bugs, Coverage, and SDK Wave 1 Part 1: TypeScript servers: extensive unit tests + per-file 90% coverage gate #4854 and Bugs, Coverage, and SDK Wave 1 Part 2: Python servers: extensive unit tests + per-file 90% coverage gate #4855, which establish it.
• client-smoke: drive a server with the Inspector V2 (web and CLI) and an LLM client, in both spec eras (2026-07-28 and 2025-11-25, Tracker: 2026-07-28 Spec Refactor #4857). This replaces the Inspector's test-servers skill. Driving the Inspector's web client needs browser automation, so also enable the Playwright plugin in .claude/settings.json, or document the Inspector CLI as the scripted path and the web client as the hand-driven one.

Acceptance criteria

• All four skills are merged with eval cases.
• A full skills:eval re-run shows no regression in the skills that already exist.
• If this is the first skill-adding PR to merge, remove Part 3's empty-skills bootstrap allowance from verify:skills.

Branch

Targets v2/main. Closes #N won't auto-close an issue on a non-default branch, so close this one by hand on merge and move the card to Done.