Fill snippet gaps (asmdefs, .inputactions, UXML/USS, Render Graph feature, tests) and ship templates as a UPM package #44

Why it matters

Snippets and templates are copy-paste starters, but the assets Unity developers struggle with most (asmdefs, Input Action assets, UXML/USS, render features) are missing entirely, and the visual-scripting "snippet" is a README. Shipping templates as a Unity package would let users import them from Package Manager with declared dependencies, which is a distribution channel inside Unity itself.

Gaps

• No .asmdef examples (runtime, Editor, EditMode/PlayMode Tests).
• No .inputactions, UXML or USS files.
• No URP ScriptableRendererFeature / Render Graph pass, no HDRP shader, no Shader Graph Custom Function HLSL.
• No test snippets despite the testing skill.
• No Addressables, NavMesh, Cinemachine 3, Jobs/Burst, ECS, Netcode, or UI Toolkit runtime data binding snippets.
• No real visual-scripting content (custom Unit C# example, exported graph YAML).
• Templates: no third-person, top-down, mobile, or multiplayer (NGO + Relay) starter.

Suggested approach

• Add the missing snippets, prioritizing asmdefs, .inputactions, UXML/USS, a Render Graph renderer feature, and EditMode/PlayMode tests.
• Restructure templates into a UPM package (com.tmhsdigital.unity-dev-tools-samples) with Samples~/ entries installable via a git URL, declaring dependencies in package.json.

Done when

Templates are importable via Package Manager with dependencies resolved, and the listed core snippet gaps are filled.