docs: add official dependency documentation for agents

Direct agents to verified documentation indexes and version-matched APIs before implementing dependency integrations. Remove instructions for disabled Copilot.

.github/copilot-instructions.md

@@ -1,38 +0,0 @@
-# OpenPencil Copilot instructions
-
-OpenPencil is a Bun workspace for a Vue 3 + CanvasKit design editor with Tauri desktop support.
-
-## Pull request requirements
-
-- Write PR titles and bodies in English.
-- Follow `.github/PULL_REQUEST_TEMPLATE.md` exactly.
-- Remove template comments and placeholders before opening a PR.
-- Never leave dangling text like `Fixes #`, `TODO`, `TBD`, or unfinished checklist explanations.
-- Summarize what changed, why it changed, and how it was validated.
-- If a user-facing change is made, update `CHANGELOG.md`.
-- Follow `CONTRIBUTING.md` and `AGENTS.md` for repository conventions.
-
-## Validation
-
-Use Bun, not npm or Node scripts unless the package explicitly requires Node.
-
-Before proposing changes, run targeted checks when possible and document them in the PR body. For broad changes, run:
-
-```sh
-bun run check
-```
-
-Package publishing changes should also run:
-
-```sh
-bun run test:packages
-```
-
-## Code conventions
-
-- No `any` unless there is a clear typed alternative problem and a justification.
-- No non-null assertions; use guards.
-- Use `crypto.getRandomValues()`, never `Math.random()`.
-- Keep Vue components free of `<style>` blocks.
-- Use existing dependencies and Reka UI components before hand-rolling UI.
-- Preserve architecture boundaries from `AGENTS.md`.

AGENTS.md

@@ -208,6 +208,25 @@ bun run test
 
 Self-review for duplication, named shared types, precise unions, and files approaching ~600 lines. Use `structuredClone` or typed copy helpers for nested mutable data. Check existing dependencies before implementing utilities; `es-toolkit` is available for focused helpers without replacing clear native code. Read current Reka UI, VueUse, and Tailwind/tailwind-variants docs before inventing UI primitives or composables, and update local wrappers deliberately when upstream APIs changed.
 
+### Dependency documentation
+
+Before using an unfamiliar dependency API or writing a replacement utility, inspect existing project wrappers and read the relevant official documentation. Start with the indexes below, then fetch specific pages rather than entire `llms-full.txt` dumps. Match documentation to versions in the package manifests and lockfiles; verify signatures against installed types/source when versions differ. Do not guess APIs or invent primitives already supplied by dependencies.
+
+| Dependency                   | Official documentation entrypoint                                                              |
+| ---------------------------- | ---------------------------------------------------------------------------------------------- |
+| Vue                          | https://vuejs.org/llms.txt                                                                     |
+| VueUse                       | https://vueuse.org/guide/ — follow individual composable documentation.                        |
+| Reka UI                      | https://reka-ui.com/llms.txt                                                                   |
+| Tauri v2                     | https://v2.tauri.app/llms.txt                                                                  |
+| Tailwind CSS                 | https://tailwindcss.com/docs                                                                   |
+| Tailwind Variants            | https://www.tailwind-variants.org/llms.txt                                                     |
+| Motion (use the Vue section) | https://motion.dev/llms.txt                                                                    |
+| Valibot                      | https://valibot.dev/llms.txt                                                                   |
+| es-toolkit                   | https://es-toolkit.dev/llms.txt                                                                |
+| CanvasKit                    | https://skia.org/docs/user/modules/canvaskit/ and installed `canvaskit-wasm/types/index.d.ts`. |
+
+VueUse currently serves HTML homepage content at its `llms.txt` URL; Tailwind CSS and Skia have no verified index there. Use their official documentation above instead. If an index disappears or returns HTML, fall back to official API documentation, not guessed methods or unofficial generated indexes.
+
 ### Native WebView tests
 
 Native desktop interaction checks live under `tests/e2e/native/**` and run through WebdriverIO against an explicit test-only Tauri binary. Use `bun run test:native` to build and run them, or `bun run build:native-test` when only the binary is needed. The embedded WebDriver plugin is compiled only with the `native-test` Cargo feature and must never be enabled in normal development or production binaries.