fix(auth): refuse on a stuck lock, capture identity at the mkdir seam (#2082)

Copilot review round 6 — five findings (two inline, three suppressed), all
valid.

**A stale lock that cannot be cleared caused unlocked writes.** `acquireLock`
does not only *create* directories: on finding a stale one it removes it and
retries, and that removal can fail — `ENOTEMPTY` for a lock with anything
inside it, `EACCES`/`EROFS` for one we may not touch. Those surface as
ordinary non-`ELOCKED` errors, which the probe read as "locks do not work
here" and degraded on. So every Inspector on the box quietly bypassed the
*same* stuck lock and raced its writes — while the release-failure message
was telling the operator saves would keep failing until they cleared it.

`isStuckOrHeld` now discriminates on **whether the lock directory exists**
rather than on an errno taxonomy: if it is there, something holds it and we
refuse; if it is not, we genuinely could not create one and degrading is the
documented trade (#1848, #1905). Reading the state the decision is about
avoids enumerating error codes per platform — and an enumeration is exactly
what let `ENOTEMPTY` through.

**Identity was captured after the acquire promise settled.** That span
includes the library's own `utimes`/`stat` probe, so a waiter replacing our
directory inside it would have us record *the winner's* identity as our own,
after which the removal guard would accept and delete their lock. It is now
recorded in the `mkdir` callback — the moment the directory becomes ours, and
synchronous with respect to this process, so there is no window.

**The expiry advice was still wrong for `EACCES`/`EPERM`/`EROFS`.** Since the
guard `stat`s before removing, everything reaching the release catch is an
`rmdir` that was refused — and stale takeover reclaims through that same
`rmdir`. The `ENOENT` arm was unreachable for the same reason, so the branch
was dead code: removed, and the advice is now unconditional.

**`proper-lockfile` was missing from `NODE_ONLY_OPTIMIZE_DEPS_EXCLUDE`.** A
fourth externalization surface — the tsup lists configure the production
bundles, not `vite dev`, whose dep scanner would otherwise walk its
CJS/`graceful-fs`/`signal-exit` graph. Added, and `vite-base-config.test.ts`
now asserts it along with `chokidar` and `@napi-rs/keyring`, which were also
absent from that assertion.

**A test was named for something it did not exercise.** "does not treat an
unlistable directory as an empty one" was driving `ENOTDIR`, which is
deliberately treated *as* the fresh-install case, so the actual new behaviour
was untested. Split in two: one for `ENOTDIR`, and a real `EACCES` one using
a `--x` directory — `readdir` denied, a known name still reachable, which is
the asymmetry that makes "unlistable" different from "empty". Driven with a
real mode rather than a stub, since `vi.spyOn` cannot redefine an ESM
namespace export; skipped as root and on Windows, where the mode would not
bite and the test would assert nothing.

Both new tests verified by mutation.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JTHVxSu8AUgHRLvo1ntZ8H
Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/server/vite-base-config.ts

@@ -34,6 +34,14 @@ const NODE_ONLY_OPTIMIZE_DEPS_EXCLUDE = [
   // excluding it keeps Vite's dep scanner from chasing into the
   // platform-specific binaries during dev startup.
   "@napi-rs/keyring",
+  // `proper-lockfile` is reached only through `core/auth/node/file-lock.ts`
+  // — the secrets file's cross-process lock (#2082) — which the Hono
+  // `/api/servers` handlers pull in via `core/auth/node/file-secret-store.ts`.
+  // Same node-only import chain as `atomically` above, and the same reason:
+  // it is CJS with a `graceful-fs`/`signal-exit`/`retry` graph that Vite's
+  // dev scanner has no business walking. Note the tsup `external` lists do
+  // **not** cover this — they configure the production bundles, not `vite dev`.
+  "proper-lockfile",
 ] as const;
 
 export function getViteBaseConfig() {