[BUG] `Dockerfile` fails to build: outdated Rust version + missing SQLx offline cache

[qdpops]

[BUG] docker-compose up fails to build — multiple errors

Errors

1. Cargo.lock version mismatch (rust:1.75)

error: lock file version `4` was found, but this version of Cargo does not understand this lock file

2. edition2024 not stabilized (rust:1.82)

error: feature `edition2024` is required
  home-0.5.12 requires the Cargo feature called `edition2024`,
  not stabilized in Cargo 1.82.0

3. ICU crates require rustc 1.86 (rust:1.85)

error: rustc 1.85.1 is not supported by the following packages:
  icu_collections@2.2.0 requires rustc 1.86
  icu_normalizer@2.2.0 requires rustc 1.86
  idna_adapter@1.2.2 requires rustc 1.86
  ...

4. SQLx compile-time query check fails (rust:1.86)

error: set `DATABASE_URL` to use query macros online, or run `cargo sqlx prepare`
  --> crates/tunnel/src/load_balancer.rs:107:9
  |
  |         sqlx::query!(
  |             "UPDATE users SET nameserver_id = ?, updated_at = ? WHERE id = ?",

No DATABASE_URL, no .sqlx/ cache, no migration files in the repo.

5. LoadBalancerRecommendation and NameserverInfo missing Serialize

error[E0277]: the trait bound `LoadBalancerRecommendation: serde::Serialize` is not satisfied
  --> crates/server/src/routes/nameservers.rs:280:13

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `serde`
  --> crates/tunnel/src/balancer.rs:2:24

Both structs are serialized into JSON API responses but have no #[derive(Serialize)], and serde is not in crates/tunnel/Cargo.toml.

---

Fix

Dockerfile — replace rust:1.75 with rust:1.86, add SQLx cache generation step:

FROM rust:1.86 AS builder
WORKDIR /app

RUN apt-get update && apt-get install -y sqlite3 && rm -rf /var/lib/apt/lists/*
RUN cargo install sqlx-cli --no-default-features --features sqlite --quiet

COPY Cargo.toml Cargo.lock ./
COPY crates ./crates

RUN sqlite3 /tmp/build.db "\
    CREATE TABLE nameservers (\
        id INTEGER PRIMARY KEY, domain TEXT NOT NULL, public_key TEXT NOT NULL,\
        assigned_users INTEGER NOT NULL DEFAULT 0, max_users INTEGER NOT NULL DEFAULT 100,\
        is_healthy INTEGER NOT NULL DEFAULT 1, priority INTEGER NOT NULL DEFAULT 0,\
        created_at INTEGER NOT NULL DEFAULT 0, is_active INTEGER NOT NULL DEFAULT 1\
    );\
    CREATE TABLE users (id INTEGER PRIMARY KEY, nameserver_id INTEGER, updated_at INTEGER);"

RUN DATABASE_URL="sqlite:/tmp/build.db" cargo sqlx prepare --workspace -- --lib || \
    DATABASE_URL="sqlite:/tmp/build.db" cargo sqlx prepare -- --lib

RUN SQLX_OFFLINE=true cargo build --release -p server

FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y ca-certificates sqlite3 curl && rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY --from=builder /app/target/release/slipstream-panel /usr/local/bin/
RUN mkdir -p /data
EXPOSE 8080/tcp 53/udp 2222/tcp
ENTRYPOINT ["slipstream-panel"]

crates/tunnel/src/balancer.rs — add serde::Serialize to both structs:

#[derive(Debug, Clone, serde::Serialize)]
pub struct NameserverInfo { ... }

#[derive(Debug, Clone, serde::Serialize)]
pub struct LoadBalancerRecommendation { ... }

crates/tunnel/Cargo.toml — add serde dependency:

[dependencies]
serde = { workspace = true, features = ["derive"] }

.gitignore — remove Cargo.lock so builds are reproducible.