feat: add the optimize-audio and optimize-web skills

[ziyiunity]

Adds two skills covering audio and web builds.

Skill	What it covers
optimize-audio	Audio memory and DSP CPU cost — import settings, load types, sample rates, compression, mixer topology
optimize-web	WebGL/WebGPU build size and load time — compression, stripping, memory sizing, frame rate, KTX textures

How these were adapted

These skills were written for an agent that ran C# in the Editor through its own built-in tool. Here they run through the Unity CLI (unity command eval against the project's com.unity.pipeline package), so they work in any agent that can run a shell.

optimize-audio carried no host-specific C#, but all 20 of its Editor interactions went through host tools, and three things were wrong independently of that:

• Scene and asset queries were conflated. It looked for t:AudioMixer with a scene-object query, but an AudioMixer is a project asset. Now two recipes: FindObjectsByType for components, AssetDatabase.FindAssets for mixer assets.
• Recipes logged instead of returning. Debug.Log only reaches the Editor console, so a caller reading stdout got nothing. They now return their values.
• Recipes assumed variables already in scope. Each snippet runs in a fresh scope, so an audioSource or clip the recipe never resolves is a compile error. A resolution recipe was added.

Its pointers to skills that don't exist in this repo now name the underlying Unity tool instead — the Memory Profiler package and the Profiler's Audio module.

optimize-web had the same host-tool problem and, separately, three API names that don't exist. An agent following the original would have failed partway through its own pre-flight, and the failure would have looked like a broken snippet rather than a wrong instruction:

The skill said	Exists?	Correct form
PlayerSettings.WebGL.codeOptimization	no	UnityEditor.WebGL.UserBuildSettings.codeOptimization
PlayerSettings.WebGL.optimizationLevel	no	as above
PlayerSettings.managedStrippingLevel	no	PlayerSettings.GetManagedStrippingLevel(NamedBuildTarget.WebGL)

Its bundled WebOptimizer.cs had the correct forms all along — only the prose was wrong, so the two are now consistent and the skill carries a short table to stop the wrong spellings coming back. Its five See also pointers referenced skills that don't exist in this repo; those now name the underlying Unity tooling instead.

One line in that skill could not be verified: UserBuildSettings.codeOptimization lives in the WebGL build-support module, which wasn't installed in the Editor used for checking. The skill documents this and tells the agent to treat a resolution failure there as "the Web module isn't installed" rather than as a bad snippet.

Verification

Every C# snippet in both skills was compile-checked against Unity 6000.5.7f1 by prefixing if (true) return "OK";, which type-checks the whole block without executing it. A deliberately broken snippet was run as a control and failed with CS0103, so the passes are real rather than an unreachable-code artifact.

Also checked: every relative references/ and resources/ path resolves to a real file, all descriptions are within the 1,536-character listing cap, no frontmatter carries an author: field, and no skill refers to another as a slash command — they name each other instead, so the references work on hosts that don't expose skills as commands.

[AlisonDoucet]

Approving for Asset Transformer Toolkit skill

[UnityAnthony]

looks good

[chris-addison]

LGTM