# 028 — Bundle the webapp with fs-embed, drop `--static-dir`

## Summary

`fs-embed` is already a `Cargo.toml` dependency but unused (`grep -rn
"fs_embed" src/` turns up nothing) — `src/api.rs` still serves the webapp via
`ServeDir`/`ServeFile` pointed at a `--static-dir` CLI arg
(`src/main.rs:35`), which requires shipping `webapp/dist` alongside the
binary. Embed the built webapp into the binary instead so `ottyl` is a single
self-contained executable.

## Scope

- Use `fs-embed` to embed `webapp/dist` at build time.
- Wire the embedded filesystem into `src/api.rs` in place of the
  `ServeDir::new(static_dir).fallback(ServeFile::new(index_html))` setup
  (`src/api.rs:100-101`), preserving the SPA fallback-to-`index.html`
  behavior.
- Remove the `--static-dir` clap arg (`src/main.rs:30-35`) and its plumbing
  through `api::router` (`src/api.rs:91`, `src/main.rs:108`).
- Update the test helper that builds a router against a temp static dir
  (`src/api.rs:729-744`) to match the new embedding approach.
- `webapp/dist` must exist at `cargo build` time (i.e. the webapp build step
  stays a prerequisite) — document that in the README's build instructions if
  not already covered.

## Acceptance criteria

- `cargo build` (with `webapp/dist` present) produces a binary that serves
  the webapp with no `--static-dir` flag and no `webapp/dist` directory
  needed at runtime.
- `--static-dir` no longer appears in `--help` output or `Args`.
- Existing API tests pass against the embedded-filesystem router.

## Depends on

None.