docs(guide/dev): remove generic and compiler-enforced sections

[KSXGitHub]

Keep the contributing guide focused on conventions unique to this project rather than restating standard Rust practices or compiler-enforced rules.

Removed from CONTRIBUTING.md:

• #[non_exhaustive] requirement from error enum guidelines
• "Documentation Comments" section (standard Rust practice)
• "Feature Gating" section (standard Rust practice)
• "Warnings Policy" section (#![deny(warnings)] is self-enforcing)
• "Visibility" section (pub/pub(crate) is basic Rust knowledge)
• "Struct Field Ordering" section (subjective, not project-specific)
• "Macros" section (generic advice)
• Type alias pub use ... as ... example
• "Use exhaustive matching" instruction (compiler-enforced)

Updated CLAUDE.md, AGENTS.md, and copilot-instructions.md to match:

• Removed #[non_exhaustive] from custom errors line
• Removed #![deny(warnings)] line

[github-actions]

Performance Regression Reports

commit: d77805c

There are no regressions.

[Copilot]

Pull request overview

Updates the repository’s contribution guidelines by removing/condensing several style-policy sections in CONTRIBUTING.md.

Changes:

• Removes the explicit guideline to mark custom error enums as #[non_exhaustive].
• Removes the “Documentation Comments”, “Feature Gating”, and “Warnings Policy” sections.
• Tweaks the “Pattern Matching” section wording/formatting.

Comments suppressed due to low confidence (1)

CONTRIBUTING.md:219

• The Error Handling section no longer mentions marking custom error enums as #[non_exhaustive], but the example immediately below still uses #[non_exhaustive]. This is internally inconsistent for contributors; either restore the guideline bullet or remove/update the example so the guidance and sample code agree.

### Error Handling

- Define custom error enums with `#[derive(Debug, Display, Error)]` from `derive_more`.
- Minimize `unwrap()` in non-test code — use proper error propagation. `unwrap()` is acceptable in tests and for provably infallible operations (with a comment explaining why). When deliberately ignoring an error, use `.ok()` with a comment explaining why.

```rust
#[derive(Debug, Display, Error)]
#[non_exhaustive]
pub enum RuntimeError {

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[Copilot]

Pull request overview

This PR updates the repository’s contribution and agent instruction documentation by removing several previously documented style/policy guidelines (e.g., visibility rules, warnings policy, documentation comment rules) and simplifying the “custom errors” guidance.

Changes:

• Removed multiple sections from CONTRIBUTING.md (visibility, documentation comments, feature gating, struct field ordering, macros, warnings policy).
• Updated agent instruction docs (CLAUDE.md, AGENTS.md, .github/copilot-instructions.md) to drop #[non_exhaustive] and #![deny(warnings)] mentions.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
CONTRIBUTING.md	Removes several documented conventions and simplifies error-handling guidance.
CLAUDE.md	Updates the “Quick Reference” rules for agents (notably custom errors and warnings policy).
AGENTS.md	Same “Quick Reference” updates as CLAUDE.md.
.github/copilot-instructions.md	Same “Quick Reference” updates as CLAUDE.md, for Copilot instructions.

Comments suppressed due to low confidence (2)

CONTRIBUTING.md:207

• The Error Handling section no longer mentions #[non_exhaustive], but the example immediately below still includes #[non_exhaustive] (and the codebase uses it widely). This is internally inconsistent—either re-add the guideline, or remove/update the example (and any related guidance) so the section is self-consistent.

### Error Handling

- Define custom error enums with `#[derive(Debug, Display, Error)]` from `derive_more`.
- Minimize `unwrap()` in non-test code — use proper error propagation. `unwrap()` is acceptable in tests and for provably infallible operations (with a comment explaining why). When deliberately ignoring an error, use `.ok()` with a comment explaining why.

```rust
#[derive(Debug, Display, Error)]
#[non_exhaustive]
pub enum RuntimeError {

CONTRIBUTING.md:231

• This document removed the Warnings Policy note, but the crate still has #![deny(warnings)] (see src/lib.rs:6). Contributors will still hit warning-as-error failures; please reintroduce a brief note here (or point to where this policy is documented) so CONTRIBUTING matches actual build behavior.

## Setup

Install the required Rust toolchain and components before running any checks:

```sh
rustup toolchain install "$(< rust-toolchain)"
rustup component add --toolchain "$(< rust-toolchain)" rustfmt clippy

</details>



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