fix(docker): pass --shm-size so Unity 6.6+ builds work (backport)

Unity 6.6+ editors request 1GiB of shared memory and hard-fail with
"Insufficient shared memory available - if using Docker, please run the
container with --shm-size=1025M" against Docker's 64m default.

This action never passed --shm-size at all and exposed no input to work
around it, so affected users had no escape hatch whatsoever. Reported as
#840 (closed as not-planned) and again on Discord against Unity
6000.6.0f1.

Backport of the fix already merged into game-ci/cli (#239), which owns
this code going forward. Adds the dockerShmSize input, the
BuildParameters field, and the flag on both the Linux and Windows
commands, defaulting to 1025m - the value unity-test-runner has always
passed. --shm-size caps a tmpfs rather than preallocating memory, so the
default costs nothing for editors that don't need it. "0"/"none" opts
back out to Docker's own default.

Co-Authored-By: Claude Opus 5 <[email protected]>

src/model/build-parameters.ts

@@ -42,6 +42,7 @@ class BuildParameters {
   public androidSymbolType!: string;
   public dockerCpuLimit!: string;
   public dockerMemoryLimit!: string;
+  public dockerShmSize!: string;
   public dockerIsolationMode!: string;
   public containerRegistryRepository!: string;
   public containerRegistryImageVersion!: string;
@@ -167,6 +168,7 @@ class BuildParameters {
       chownFilesTo: Input.chownFilesTo,
       dockerCpuLimit: Input.dockerCpuLimit,
       dockerMemoryLimit: Input.dockerMemoryLimit,
+      dockerShmSize: Input.dockerShmSize,
       dockerIsolationMode: Input.dockerIsolationMode,
       containerRegistryRepository: Input.containerRegistryRepository,
       containerRegistryImageVersion: Input.containerRegistryImageVersion,