Add playground to nav, open-in-playground buttons, deps migration

.gitignore

@@ -2,9 +2,8 @@
 
 /target
 /build
+/.deps
 
 /.claude/settings.local.json
 /.claude.local/
 
-/playground/node_modules/
-/playground/src/placeholder.wasm

CLAUDE.md

@@ -5,37 +5,48 @@
 All dependency versions are declared in one place:
 
 - **Rust crates**: `Cargo.toml` `[dependencies]`
-- **Asset dependencies** (e.g. playground artifact): `Cargo.toml` `[package.metadata.assets.<name>]`
+- **Asset dependencies** (e.g. playground, brand): `Cargo.toml` `[package.metadata.assets.<name>]`
 
 ### Updating dependencies
 
 Run `cargo run -- update-deps` to update all dependencies:
 
 1. Runs `cargo update` (Rust crates)
-2. Downloads asset dependencies from GitHub releases into `build/assets/`
+2. Downloads asset dependencies from GitHub releases into `.deps/`
 
 ### Build vs fetch
 
-- `cargo run` (or `cargo run -- build`) builds with what is already in `build/assets/`. It will error if a referenced asset is missing.
+- `cargo run` (or `cargo run -- build`) builds with what is already in `.deps/`. It will error if a referenced asset is missing.
 - `cargo run -- update-deps` fetches/updates dependencies. It does not build.
 - A clean build should never fetch dependencies.
 
-## Build output
+## Project layout
 
 ```
+.deps/              # downloaded dependencies — NOT wiped by build, gitignored
+  playground/       # playground artifact (JS/WASM/CSS)
+  brand/            # brand assets (logo SVGs, favicon PNGs, social image)
 build/
-  assets/     # downloaded dependencies — NOT wiped by build
-  site/       # generated output — wiped on each build
+  site/             # generated output — wiped on each build
+static/             # static files copied verbatim to build/site/
+                    # (brand assets here are fallbacks, overridden by .deps/brand/)
 ```
 
-`build/` is gitignored. The dev server (`cargo run -- serve`) serves from `build/site/`.
+The dev server (`cargo run -- serve`) serves from `build/site/`.
+
+## Brand assets
+
+Brand assets (logo, favicons, social image) come from the `brand` dependency.
+The build copies them from `.deps/brand/assets/` into `build/site/`, overriding
+any fallback files in `static/`. Once the brand release is live, the fallback
+copies in `static/` can be removed.
 
 ## Fragment injection
 
-Content pages can inject HTML fragments from `build/assets/` using frontmatter:
+Content pages can inject HTML fragments from `.deps/` using frontmatter:
 
 ```yaml
-fragment: playground/fragment.html   # path relative to build/assets/
+fragment: playground/fragment.html   # path relative to .deps/
 asset_dir: playground                # copies runtime files to build/site/<path>
 ```
 

Cargo.toml

@@ -6,12 +6,19 @@ edition = "2024"
 [package.metadata.assets.playground]
 url = "https://github.com/fink-lang/playground/releases/download/{version}/playground.tar.gz"
 version = "v1.9.0"
-dest = "build/assets/playground"
+dest = ".deps/playground"
+
+[package.metadata.assets.brand]
+url = "https://github.com/fink-lang/brand/releases/download/{version}/brand-assets.tar.gz"
+version = "v1.0.0"
+dest = ".deps/brand"
 
 [dependencies]
-fink = { git = "https://github.com/fink-lang/fink.git", branch = "main" }
+fink = { git = "https://github.com/fink-lang/fink.git", tag = "v0.1.0" }
 pulldown-cmark = "0.13"
 tera = "1"
 walkdir = "2"
 anyhow = "1"
 tiny_http = "0.12"
+flate2 = "1"
+image = { version = "0.25", default-features = false, features = ["png"] }