Enforce workspace Clippy standards and document lint policy

AGENTS.md

@@ -58,7 +58,7 @@ People trust PhotoCraft with their work, and a crash loses it. A malformed file,
 - **Don't cascade.** Handle lock poisoning (`lock().unwrap_or_else(PoisonError::into_inner)`) and treat thread joins as `Result`s.
 - **Last-resort guard.** The app shell must catch an escaped panic around command dispatch and file import/export, reports it as an error and keeps the document. It's a safety net, not a licence to panic. Keep `panic = "unwind"`.
 - **Prove it.** Every crash fix comes with a small synthetic regression test that panicked before the fix.
-- **Enforced by clippy.** `clippy.toml` allows `unwrap`/`expect`/`panic`/indexing in tests only. Clean crates carry `#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]`; new crates start with it.
+- **Enforced by clippy.** `clippy.toml` allows `unwrap`/`expect`/`panic` in tests only. Clean production crate roots carry `#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]`; every new workspace crate must also include `[lints] workspace = true` in `Cargo.toml` to inherit `[workspace.lints]`.
 
 1. **Everything is a command.** New user-visible behaviour = a command in the engine (`crates/engine/src/*_cmds.rs`, registered in `commands.rs`) with id, label, menu path, shortcut, params doc, `enabled` and `run`, plus tests. The UI, CLI, control channel and MCP all dispatch commands by id. Use the **exact id from `crates/ui-egui/src/menu_catalog.rs`** and the menu item goes live automatically. Only pure view/window state (zoom, panels, screen mode) belongs to the shell (`menus.rs` `UI_COMMANDS`).
 2. **No format or colour assumptions.** Bit depth (8/16/32f) and colour model (RGB/Gray/CMYK/Lab…) are runtime data. Never introduce a `u8`-only pixel path in public APIs. Never assume sRGB: colour conversions go through `photocraft-cms` (`Transform`, `transform::cached`). Test at several depths.

Cargo.toml

@@ -76,6 +76,9 @@ web-time = "1"
 unsafe_code = "forbid"
 
 [workspace.lints.clippy]
+cognitive_complexity = "deny"
+too_many_arguments = "deny"
+wildcard_imports = "deny"
 dbg_macro = "warn"
 todo = "warn"
 

clippy.toml

@@ -5,3 +5,4 @@ allow-indexing-slicing-in-tests = true
 disallowed-types = [
     { path = "egui::ComboBox", reason = "use craft_ui::ComboBox: egui's combo box menu can't grow back while open (egui#5225)" },
 ]
+cognitive-complexity-threshold = 30