v0.4.5: VMware UEFI fix, static musl binary, Forms auth + SSO config

VMware UEFI / Casper boot fix:
- Linux cmdline for Debian/Ubuntu/Mint/Pop!_OS/elementary now uses the
  canonical Casper `iso-url=` option and `ds=nocloud`, matching the
  fix Bootimus shipped in v0.1.67. The previous
  `boot=casper netboot=url url=… ip=dhcp ---` form booted fine on
  bare-metal UEFI but hung at "cloud-init running" on VMware guests
  because subiquity / cloud-init can't reach a metadata datasource
  through PXE.

Static binary (matches Bootimus v0.1.70):
- Dockerfile build stage now compiles against
  x86_64-unknown-linux-musl. The resulting /openpxe has no glibc
  dependency at all; the runtime stage still ships Debian slim for the
  samba/wimtools/nfs-common shellouts, but a future scratch/distroless
  variant is now a one-line swap. Cuts a class of "GLIBC_2.39 not
  found" surprises on older RHEL/Rocky hosts.

Forms auth (Sonarr/Radarr-style):
- New AdminStore in openpxe-core: single admin record persisted to
  <work_dir>/auth.json, bcrypt-hashed credentials, rotation requires
  current password.
- New SessionStore in openpxe-http-api: in-memory UUID-keyed sessions
  with 24h sliding TTL, openpxe_session HttpOnly cookie.
- Endpoints: POST /api/setup (first-run), POST /api/login, POST
  /api/logout, GET /api/me, PUT /api/me/credentials (rotates and
  revokes every other session).
- Auth middleware gates /api/* once the admin is configured;
  passes through entirely until then (tests + fresh installs ride this
  path). Allowlists PXE-essential paths (/boot.ipxe, /iso/*, /ipxe/*,
  /api/queue/join, /api/queue/poll/*) so iPXE clients still work
  without a cookie they can't send.
- WebUI: first-run setup card, login card, logout chip in the sidebar
  footer, Account card in Settings for rotating creds. Auth screen is
  fully styled (centered narrow card, matches Sonarr layout).

SSO config (FleetDM-shaped, storage-only):
- New SsoStore in openpxe-core: { enabled, idp_name, metadata,
  metadata_url } persisted to <work_dir>/sso.json with size caps and
  URL-scheme validation.
- Endpoints: GET /api/sso, PUT /api/sso. Validation: enabling SSO
  without either metadata or metadata_url returns 400.
- WebUI: SSO card in Settings with a URL-vs-XML mode switch and an
  inert "Sign in with X" button on the login screen while runtime
  flow is pending. Per the brief: no Entity ID field (defaults to the
  advertised public_base_url internally when SAML wiring lands).

Quality:
- 132 tests passing (was 106 in v0.4.4): +5 auth unit tests, +5 SSO
  unit tests, +7 auth integration tests, +1 SSO integration test, +1
  regression guard pinning the new Casper cmdline.
- cargo clippy --workspace --all-targets clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

deploy/docker/Dockerfile

@@ -28,6 +28,22 @@ RUN mkdir -p assets/ipxe && bash scripts/fetch-ipxe.sh
 FROM rust:${RUST_VERSION}-bookworm AS build
 WORKDIR /src
 
+# v0.4.5: build a fully static musl binary (matches Bootimus v0.1.70's
+# move). The resulting `/openpxe` has no glibc dependency at all, which:
+#   - Lets the runtime stage be any Linux distro (we still ship Debian
+#     slim for the `samba` / `wimtools` / `nfs-common` shellouts, but a
+#     scratch/distroless variant becomes a one-line swap).
+#   - Cuts a class of "GLIBC_2.39 not found" surprises when running on
+#     older RHEL/Rocky hosts that don't match Debian 12's libc version.
+#   - Sidesteps cross-compilation snags (the binary is its own world).
+#
+# x86_64-unknown-linux-musl is fully static by default (no extra
+# RUSTFLAGS needed). musl-tools provides the linker.
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends musl-tools \
+ && rm -rf /var/lib/apt/lists/* \
+ && rustup target add x86_64-unknown-linux-musl
+
 # Copy the whole workspace in one go. We used to do a two-pass "cache-prime
 # with stubs, then real build" dance for dep-compile reuse; that turned out
 # to silently serve stale stub binaries when cargo's fingerprint didn't
@@ -42,14 +58,14 @@ COPY Cargo.toml Cargo.lock ./
 COPY crates/ crates/
 COPY --from=fetch /src/assets/ipxe /src/assets/ipxe
 
-# Cache cargo registry + target across builds. The `--no-edit` touch is
+# Cache cargo registry + target across builds. The mtime touch is
 # belt-and-suspenders: cargo occasionally misses mtime-only changes on
 # networked FS; this forces a fingerprint check.
 RUN --mount=type=cache,target=/usr/local/cargo/registry \
     --mount=type=cache,target=/src/target,sharing=locked \
     find crates -name '*.rs' -exec touch {} + && \
-    cargo build --release --bin openpxe && \
-    cp target/release/openpxe /openpxe && \
+    cargo build --release --target x86_64-unknown-linux-musl --bin openpxe && \
+    cp target/x86_64-unknown-linux-musl/release/openpxe /openpxe && \
     ls -l /openpxe
 
 ########## runtime ##########
@@ -62,22 +78,28 @@ RUN apt-get update \
  && useradd --system --uid 10001 --home-dir /var/lib/openpxe --shell /usr/sbin/nologin openpxe \
  && mkdir -p /var/lib/openpxe/isos /var/lib/openpxe/work /var/lib/openpxe/smb \
  && chown -R openpxe:openpxe /var/lib/openpxe
-# Runtime deps explained:
-#   wimtools  - provides `wimlib-imagex`, used to inject startnet.cmd into boot.wim.
-#   samba     - `smbd` serves extracted Windows install media on :445 for WinPE
-#               to `net use`. Guest read-only, scoped to /var/lib/openpxe/smb.
-#   nfs-common - provides `mount.nfs` / `mount.nfs4` for the Storage tab's
-#               NFS share manager. Mount also requires the container to run
-#               with CAP_SYS_ADMIN — without it, mount(2) returns EPERM and
-#               the manager surfaces a clear error in the UI instead of
-#               failing silently.
-#   iproute2  - `ip addr` / `ip route` for the auto-detected Network tab
-#               fields (NIC name, subnet mask, default gateway). Tiny,
-#               always available; we don't pull in netlink crates for
-#               this one-shot startup probe.
-#   gosu      - drops privileges cleanly from root after the entrypoint fixes
-#               bind-mount ownership (common OpenShift/Docker UX issue).
-# Windows-specific tools only activate when the WebUI toggle is on.
+# v0.4.5: the openpxe binary itself is now built against musl and is
+# fully static — no glibc dependency. The runtime stage still ships
+# Debian slim because OpenPXE shells out to the four packages below for
+# functionality we deliberately don't reimplement in-process:
+#   wimtools   - `wimlib-imagex`, used to inject startnet.cmd into boot.wim.
+#   samba      - `smbd` serves extracted Windows install media on :445 so
+#                WinPE can `net use`. Guest read-only, scoped to
+#                /var/lib/openpxe/smb.
+#   nfs-common - `mount.nfs` / `mount.nfs4` for the Storage tab's NFS
+#                share manager. Mount requires CAP_SYS_ADMIN; without it
+#                mount(2) returns EPERM and the manager surfaces a clear
+#                error in the UI.
+#   iproute2   - `ip addr` / `ip route` for the auto-detected Network
+#                tab fields (NIC name, subnet mask, default gateway).
+#                Tiny, always available; we don't pull in netlink crates
+#                for this one-shot startup probe.
+#   gosu       - drops privileges cleanly from root after the entrypoint
+#                fixes bind-mount ownership (common OpenShift/Docker UX
+#                issue).
+# A future "openpxe-static" variant could drop everything except the
+# binary onto distroless once we move the Windows + NFS legs to
+# in-process Rust crates.
 
 COPY --from=build /openpxe /usr/local/bin/openpxe
 COPY deploy/docker/entrypoint.sh /usr/local/bin/entrypoint.sh