docs(workspace): document lint-suppression policy

AGENTS.md

@@ -107,6 +107,15 @@ Subsystems that are I/O- or hardware-bound — the `renderer`/Vulkan GPU paths,
 
 Unit tests live beside the code (`#[cfg(test)] mod tests`) and run with `cargo test -p <crate>`.
 
+## Lint suppressions
+
+The workspace opts into strict linting: Clippy's `pedantic` group plus restriction lints that ban `unwrap`, `expect`, and `print` outside the permitted contexts (see `[workspace.lints]` in the root `Cargo.toml`). Suppressions are therefore expected at specific sites, and are governed by these rules:
+
+- **Prefer `#[expect(...)]` over `#[allow(...)]`** for a localised suppression. An `#[expect]` becomes a warning (`unfulfilled_lint_expectations`) if the lint it names no longer fires, so an obsolete suppression surfaces and is removed instead of lingering silently. `#[allow]` never self-reports and accumulates into dead noise.
+- **Suppress narrowly.** Name the exact lint(s), and attach the attribute to the smallest scope that covers the site — a statement, expression, or item — never a broad crate-level `#![allow]`. The sole standing exception is a deliberate crate-wide policy, such as `#![allow(unsafe_code)]` in `renderer`, where the suppression is the architectural intent rather than a local waiver.
+- **Justify non-obvious suppressions.** Where the reason a lint is safe to suppress is not self-evident from the surrounding code, precede the attribute with a brief comment stating why (for example, that a cast is provably in range).
+- **Never suppress `correctness`-tier lints.** Those indicate real defects; fix the code instead.
+
 ## Documentation style
 
 - **Objective Tone:** All comments (both doc comments `///` and inline `//`) must be written in a formal, objective, and neutral tone.