refactor(skills): cut style, philosophy, and typescript to five rules each

[TheGreatAxios]

Summary

• Delete the style (3,400 words) and philosophy (1,000) skills. Five rules that change behavior move into the shared scope-and-conventions block of the system prompt, so the primary and every worker get them: keep refactors out of features and do work now, comments explain why, delete replaced paths without shims, fix at the layer that owns the invariant, validate at the boundary and land tests with the change. Commit-message rules stay in CONTRIBUTING.md, which AGENTS.md already makes authoritative.
• Rewrite typescript (2,400 words) as five headline rules with short examples (about 300 words): real types, validate at the boundary, functions and named exports, errors keep their cause, bun:test tests that prove behavior.
• Drop the "load style and philosophy" instructions from AGENTS.md, the primary prompt, and refactor, and remove both names from the telemetry allowlist and docs.

Verification

• bun run check green (7,870 tests).
• Convention text drops from about 6,800 words to about 400.

Fixes CL-9648

[linear-code]

CL-9648