[Kinflou]

Step 4 of the core 2ae9986 cascade, and the CLI side of comline.toml editor support (generation#92).

• Shared config. comline.toml's types, parsing and resolution are now comline_codegen::config, and the moved code is gone from src/gen_config.rs. That file keeps only Destination::dest_for, which renders a target's layout into a path with core's template engine. external::DEFAULT_TIMEOUT is config::DEFAULT_TIMEOUT. Behaviour and error messages are unchanged. The moved unit tests now run in generation.
• #:schema. comline new's comline.toml starts with #:schema https://comlineproject.github.io/docs/schemas/comline-toml/0.x.json. The scaffold test asserts that line. It's a TOML comment, and the scaffold test still builds and generates from the project.
• docs/cli.md describes the schema and the #:schema line, and corrects mode to code | lib.
• Pins:
  • core 2ae9986 (core#148)
  • comline-codegen generation de7ceb4, the same string comline-rust and comline-typescript pin
  • comline-codegen-rust 5346678 (comline-rust#84)
  • comline-codegen-typescript c2096cd (comline-typescript#100)
  • the same in tests/fixtures/generators
• One test fixture change, from core#148. A framing without conformance vectors now gives up encoding conformance. The dependency-framing tests' acme package therefore ships lines.vectors.json beside its profile, copied from tests/fixtures/conformance_package.

Output check. I ran comline generate with main and with this branch on simple_project, validated_project, chat_project and conformance_package. Each ran under 8 comline.toml variants: default, lib, lib with inline std, custom layout/out/async/validate, only + flattened target, a bad mode, a typo'd key, and default_framing.

• All generated files, stdout/stderr and exit codes are identical, apart from one line in the Rust output.
• That line is the comline-runtime rev comment or Cargo.toml dependency (4d6e1c5 → 37082de). It comes from comline-rust#82, already on comline-rust main, which this branch picks up by moving off 0e5c60e.

cargo fmt --check, both clippy configurations and cargo test (13 + 105) pass locally. cargo tree -d shows one copy of each comline crate.

Merge after generation#92, comline-rust#84 and comline-typescript#100.