Rjf/update codegen

[robfitzgerald]

i was reviewing the codegen crate and found that code changes in the core crate had broken the templates.

this PR rewrites the routee-compass-codegen crate so that the source template material is wired into the RouteE Compass codebase and therefore compiled. if any changes happen to the definitions for traversal/constraint/input plugin/output plugin traits, it will break the code in the codegen crate, forcing the developer to update those templates. this simplifies the task of ensuring that they remain up-to-date, relying on the developer to honor maintaining those files along with any changes to core trait APIs.

all template code avoids making references to the crate routee-compass-codegen so that, on fs copy, the files are internally linked and do not break references.

along the way,

• i added codegen templates for Constraint, InputPlugin and OutputPlugin modules.
• instead of offering users to decide if they want to use an engine.rs file for traversal/constraint models, we now only support generation with an engine.rs file, favoring a simpler codebase and being more opinionated.

each template module is flagged with #[allow_unused] to avoid sending warnings.

[Copilot]

Pull request overview

This PR rewrites the routee-compass-codegen crate to embed the codegen templates as real, compiled Rust modules (Traversal, Constraint, InputPlugin, OutputPlugin) and switches the CLI to a generic “copy selected template files” flow, so core API changes break compilation and force template updates.

Changes:

• Replaced per-component generators with a unified generate_module that reads template source files from the crate and copies them into a new module directory.
• Added compiled template modules for Traversal, Constraint, InputPlugin, and OutputPlugin (with stubbed todo!() implementations).
• Updated the cargo compass CLI to support selecting which template files to copy (and added --force to more subcommands).

Reviewed changes

Copilot reviewed 33 out of 33 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
rust/routee-compass-codegen/Cargo.toml	Adds dependencies needed for compiled templates (core/app crates, serde_json, thiserror).
rust/routee-compass-codegen/src/main.rs	Updates CLI to use a file-list based generator flow and adds --force in more commands.
rust/routee-compass-codegen/src/generator/mod.rs	Reorganizes generator module; adds component type + error + run module and includes templates with #[allow(unused)].
rust/routee-compass-codegen/src/generator/component_type.rs	Adds component enum and template file retrieval from embedded source tree.
rust/routee-compass-codegen/src/generator/error.rs	Introduces typed errors for template read failures.
rust/routee-compass-codegen/src/generator/run.rs	Implements unified module generation + overwrite-protected file writing.
rust/routee-compass-codegen/src/generator/util.rs	Removes old standalone write helper (functionality moved into run.rs).
rust/routee-compass-codegen/src/generator/traversal/mod.rs	Adds compiled traversal template module layout/exports.
rust/routee-compass-codegen/src/generator/traversal/builder.rs	Adds traversal builder template (compiled).
rust/routee-compass-codegen/src/generator/traversal/config.rs	Adds traversal config template (compiled).
rust/routee-compass-codegen/src/generator/traversal/engine.rs	Adds traversal engine template (compiled).
rust/routee-compass-codegen/src/generator/traversal/model.rs	Adds traversal model template (compiled).
rust/routee-compass-codegen/src/generator/traversal/params.rs	Adds traversal params template (compiled).
rust/routee-compass-codegen/src/generator/traversal/service.rs	Adds traversal service template (compiled).
rust/routee-compass-codegen/src/generator/traversal.rs	Removes old string-template generator implementation.
rust/routee-compass-codegen/src/generator/constraint/mod.rs	Adds compiled constraint template module layout/exports and module docs.
rust/routee-compass-codegen/src/generator/constraint/builder.rs	Adds constraint builder template (compiled).
rust/routee-compass-codegen/src/generator/constraint/config.rs	Adds constraint config template (compiled).
rust/routee-compass-codegen/src/generator/constraint/engine.rs	Adds constraint engine template (compiled).
rust/routee-compass-codegen/src/generator/constraint/model.rs	Adds constraint model template (compiled).
rust/routee-compass-codegen/src/generator/constraint/params.rs	Adds constraint params template (compiled).
rust/routee-compass-codegen/src/generator/constraint/service.rs	Adds constraint service template (compiled).
rust/routee-compass-codegen/src/generator/constraint.rs	Removes old placeholder constraint generator.
rust/routee-compass-codegen/src/generator/input_plugin/mod.rs	Adds compiled input plugin template module layout/exports.
rust/routee-compass-codegen/src/generator/input_plugin/builder.rs	Adds input plugin builder template (compiled).
rust/routee-compass-codegen/src/generator/input_plugin/config.rs	Adds input plugin config template (compiled).
rust/routee-compass-codegen/src/generator/input_plugin/plugin.rs	Adds input plugin implementation template (compiled).
rust/routee-compass-codegen/src/generator/input_plugin.rs	Removes old placeholder input plugin generator.
rust/routee-compass-codegen/src/generator/output_plugin/mod.rs	Adds compiled output plugin template module layout/exports.
rust/routee-compass-codegen/src/generator/output_plugin/builder.rs	Adds output plugin builder template (compiled).
rust/routee-compass-codegen/src/generator/output_plugin/config.rs	Adds output plugin config template (compiled).
rust/routee-compass-codegen/src/generator/output_plugin/plugin.rs	Adds output plugin implementation template (compiled).
rust/routee-compass-codegen/src/generator/output_plugin.rs	Removes old placeholder output plugin generator.

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