Add llama.cpp backend, model gateway, URL relay and browser view

Four features, plus a latent bug fix.

llama.cpp backend. Claude Code only ever speaks the Anthropic Messages
API — confirmed empirically by pointing it at a logging server, which
received POST /v1/messages?beta=true. llama-server implements that
natively (verified in its README, alongside --port default 8080), so
this is a plain base-URL backend with no translation shim, the same
shape as Ollama. Its --api-key defaults to none, so the auth token is a
placeholder Claude Code requires and llama-server ignores.

Model alias fix. ANTHROPIC_DEFAULT_HAIKU_MODEL is documented as "also
used for background functionality", and Triple-C set none of the alias
vars. So on every custom-endpoint backend, Claude Code resolved `haiku`
to an Anthropic model id and sent it to a local server that does not
have it — background features failed silently. All four
ANTHROPIC_DEFAULT_{OPUS,SONNET,HAIKU,FABLE}_MODEL vars are now pinned to
the backend's configured model, with an optional Haiku override, and
blanked for Anthropic and Bedrock so those keep Claude Code's defaults.
The deprecated ANTHROPIC_SMALL_FAST_MODEL is never emitted. Existing
Ollama and OpenAI-Compatible containers are recreated once so the new
env reaches them; the snapshot is preserved.

Model gateway. Optional LiteLLM sibling container, off by default,
mirroring stt.rs — this is what makes real OpenAI usable, since
api.openai.com has no /v1/messages. Pinned to v1.96.0 by tag and digest:
the 1.82.7/1.82.8 malware was PyPI-only and never affected the official
images, which is precisely why this builds FROM the image rather than
pip-installing, but 1.84.0 is still the floor for proxy CVEs (API-key
SQLi, Host-header auth bypass, MCP auth bypass). Binds 0.0.0.0 because
project containers consume it, and therefore always sets a master_key —
LiteLLM without one accepts any key. The provider key lives in the OS
keychain and is uploaded into a volume, never an image layer or label.

URL relay. A container-side xdg-open/BROWSER shim opens URLs in the
host's browser. Uses an OSC sequence to /dev/tty rather than a printed
sentinel, because the shim usually runs as a grandchild of a process
capturing its children's output. Degrades to printing the URL when no
terminal is attached, so scheduled tasks do not hang. Only http/https,
with control characters rejected before new URL() — which strips
newlines, so java\nscript: would otherwise parse as javascript:. Nothing
auto-opens; the user confirms. The web terminal shows a tap-to-open
banner instead, since that browser may be a phone across a tunnel.

Browser view. A Project Home tab that watches and takes over the browser
Claude drives with Playwright, using Playwright's own dashboard. Zero
image cost — Playwright stays user-installed. It does not reuse the auth
bridge's PortForward, which binds an unauthenticated port: correct for a
throwaway OAuth listener, wrong for mouse and keyboard control of a
browser in a passwordless-sudo container. Instead a token-gated loopback
proxy checks Host, then token or a forbidden-header origin signal,
before a byte reaches the container. Host ports are confined to
47820..=47827 so CSP frame-src can enumerate them rather than widening
to a wildcard, with a test asserting the two agree.

188 frontend tests, 107 Rust tests, both builds clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src-tauri/src/auth_bridge/tunnel.rs

@@ -172,6 +172,24 @@ async fn accept_optional(
 
 /// Carry one accepted host connection into the container over `socat`.
 async fn tunnel_connection(container_id: String, target: String, stream: TcpStream, port: u16) {
+    tunnel_connection_with_prelude(container_id, target, stream, port, Vec::new()).await
+}
+
+/// As [`tunnel_connection`], but `prelude` is written into the container first,
+/// ahead of anything further read from `stream`.
+///
+/// This exists for callers that must *inspect* the beginning of a connection
+/// before deciding to forward it — the browser-view proxy reads the HTTP request
+/// head off the socket to check a token, and then has to put those same bytes
+/// back on the wire. Passing them here keeps the byte stream exact, rather than
+/// re-serialising a parsed request.
+pub async fn tunnel_connection_with_prelude(
+    container_id: String,
+    target: String,
+    stream: TcpStream,
+    port: u16,
+    prelude: Vec<u8>,
+) {
     let cmd = vec!["socat".to_string(), "-".to_string(), target.clone()];
 
     let AttachedExec {
@@ -198,6 +216,13 @@ async fn tunnel_connection(container_id: String, target: String, stream: TcpStre
     // direction drops `input`, which closes the exec's stdin and lets socat see
     // a clean EOF (a half-close, not a teardown of the whole connection).
     let upstream = AbortOnDrop(tokio::spawn(async move {
+        // Bytes the caller already consumed from the socket go first, so the
+        // container sees the connection exactly as the client sent it.
+        if !prelude.is_empty()
+            && (input.write_all(&prelude).await.is_err() || input.flush().await.is_err())
+        {
+            return;
+        }
         let mut buf = vec![0u8; PUMP_BUF];
         loop {
             match host_rx.read(&mut buf).await {