add agent rules

.opencode/opencode.json

@@ -1,4 +1,5 @@
 {
 	"$schema": "https://opencode.ai/config.json",
 	"plugin": ["@sveltejs/opencode"],
+	"instructions": [".opencode/rules/*.md"]
 }

.opencode/rules/formatting.md

@@ -0,0 +1,16 @@
+# Formatting
+
+## Command
+
+- `pnpm format` writes formatted code (Prettier).
+- `pnpm lint` verifies formatting plus ESLint; use it as the check.
+
+## Prettier
+
+- `.prettierrc` is the source of truth for all Prettier settings. Read it rather than assuming defaults; if its values change, follow the file.
+- Do not hand-format to match remembered settings — run `pnpm format` and let Prettier decide.
+- `.prettierignore` lists files Prettier skips (lockfiles, `build/`, `node_modules/`, etc.). Respect it.
+
+## Tailwind class ordering
+
+- `prettier-plugin-tailwindcss` sorts utility class names automatically. Never manually reorder classes for sorting — just run `pnpm format`.

.opencode/rules/linting.md

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+# Linting
+
+## Command
+
+- Run `pnpm lint` (Prettier check + ESLint) before finishing any work.
+- If `pnpm lint` reports errors, fix them and re-run until clean.
+- Never leave the repo in a state where `pnpm lint` fails.
+
+## ESLint
+
+- The flat config in `eslint.config.js` is the source of truth for enabled rules. Read it before making lint-related assumptions.
+- `.svelte` files are handled by `eslint-plugin-svelte` with the TypeScript parser.
+- `eslint.config.js` respects `.gitignore` — don't lint `build/`, `.svelte-kit/`, or `node_modules/`.
+- Prefer fixing the root cause over suppressing: avoid `eslint-disable` comments unless truly necessary, and never disable an entire file.
+- Run `pnpm lint` for the whole project after edits that touch Svelte, TypeScript, or configuration files.

.opencode/rules/tailwind.md

@@ -0,0 +1,20 @@
+# Tailwind CSS + daisyUI
+
+## Version and integration
+
+- Tailwind CSS 4 via the `@tailwindcss/vite` plugin. Configuration is CSS-first.
+- Global theming and daisyUI plugin setup live in `src/app.css` — read it for the current theme names and page background setup. It is the source of truth for theme configuration.
+- `tailwind.config.ts` only defines content globs. Do not add JS theme tokens there; use CSS-first `@theme` in `src/app.css` instead.
+
+## Style rules
+
+- Prefer Tailwind utilities and daisyUI component classes (e.g. `btn`, `card`, `badge`) and their theme colors over hand-written CSS.
+- Avoid arbitrary values (`[ ... ]`) when a core utility exists.
+- Add new design tokens via `@theme` in `src/app.css`, not in `tailwind.config.ts`.
+- Put page/component styling in `src/routes/**` components with utilities; keep global styles in `src/app.css`.
+- Static assets referenced by URL (e.g. `/background.jpg`) live in `static/`.
+
+## Verification
+
+- After styling changes, run `pnpm check` (Svelte typecheck) and `pnpm build`.
+- Class ordering is handled by `prettier-plugin-tailwindcss` — run `pnpm format` rather than reordering classes by hand.