refactor: adopt drafter terminology

[rlippmann]

Summary

Migrate the Python integrations to context-compiler-directive-drafter dev5, adopt the dev5 fallback APIs and LiteLLM adapter, and complete the Drafter terminology cleanup.

Changes

• Update the Python dependency and lockfile to context-compiler-directive-drafter==0.2.0dev5.
• Use dev5 fallback profiles and the LiteLLM fallback adapter in the standalone example and LiteLLM Proxy reference integration.
• Use the dev5 fallback profile in the Open WebUI Drafter pipe.
• Migrate integration tests to dev5 rejection reasons, sentinels, and fallback behavior.
• Remove obsolete prompt-profile configuration.
• Use DRAFTER_MODEL and DRAFTER_MODEL_ID exclusively.
• Remove the old PREPROCESSOR_MODEL* compatibility names and warnings as an intentional hard break.
• Expose ContextCompilerPreCallHookWithDrafter only; remove the old class alias.
• Preserve generic preprocessing terminology in the non-Drafter Open WebUI base pipe.
• Bump the Open WebUI Drafter pipe frontmatter version to 0.10.2.

Why

The integrations now match the published dev5 public API and consistently describe the acquisition stage as Drafter. This branch deliberately does not preserve the obsolete preprocessor configuration or class names.

Example metadata

• Enforcement point: repository maintenance / integration compatibility
• Domain: N/A
• Technology/runtime: Python, LiteLLM, LiteLLM Proxy, Open WebUI
• Example type: reference integration / repository maintenance
• Does this use directive drafter? yes
• Does this derive state from model output? no; Context Compiler remains the authority for state

Checklist

• Repository scaffolding / governance change
• One primary enforcement point
• Explicit authoritative state
• No model-derived state mutation
• Adversarial stub or equivalent test
• Observable runtime behavior change
• Domain vocabulary is natural
• Framework is secondary to the enforcement point
• Docs updated
• Tests/smoke checks added where practical

Validation

• Focused Drafter integration tests: 55 passed
• Full Python validation: 210 passed, 6 skipped
• Markdown lint: 0 issues
• Ruff and mypy: passed
• git diff --check: passed