In `@src/Migration/Destinations/Appwrite.php`:
- Around line 215-222: The call to Framework::STATIC() is invalid for Appwrite
v19.1.0 and will fatal; update the Sites creation in Appwrite.php by removing or
replacing Framework::STATIC() in the $this->sites->create(...) call inside the
Resource::TYPE_SITE block: either drop the framework argument if optional, or
map the incoming 'static' value to the correct Framework enum (e.g.,
Framework::REACTSTATIC or another valid Framework constant) before calling
$this->sites->create; update any other occurrences (e.g., the earlier match
handling that uses Framework::STATIC()) to perform the same mapping so the code
uses a valid Framework enum instead of Framework::STATIC().

In `@src/Migration/Transfer.php`:
- Around line 39-43: exportGroupSites currently only triggers exportSites() when
Resource::TYPE_SITE is requested, so requesting Resource::TYPE_SITE_VARIABLE
alone omits variables; update exportGroupSites() to also check for
Resource::TYPE_SITE_VARIABLE and either call exportSites() when variables are
requested or add a separate code path to export variables from exportSites()
output. Modify the conditional that tests for Resource::TYPE_SITE to include
Resource::TYPE_SITE_VARIABLE (or add an explicit branch handling
Resource::TYPE_SITE_VARIABLE) so site variables are exported even if TYPE_SITE
is not present, referencing the GROUP_SITES_RESOURCES constant and using
existing exportSites() logic to perform the actual extraction.

In `@src/Migration/Destinations/Appwrite.php`:
- Around line 1542-1635: The code uses Appwrite enums (Framework, Adapter,
BuildRuntime) that may not exist in the installed SDK and will throw fatal
errors; replace enum usage in the match blocks (the mappings that assign
$framework, $adapter, $buildRuntime from
$resource->getFramework()/getAdapter()/getBuildRuntime()) with plain string
values (or a validated string mapping) instead of Framework::*, Adapter::*,
BuildRuntime::* calls, or alternatively add a runtime guard (class_exists for
each enum) and fallback to the raw string when the enum class is missing; update
the match blocks in src/Migration/Destinations/Appwrite.php (the $framework,
$adapter, $buildRuntime assignments) to return strings (e.g., 'react', 'static',
'node-18.0') or use a safe mapping and remove direct enum references unless the
SDK dependency is constrained to a release that includes those enum classes.

In `@src/Migration/Destinations/Appwrite.php`:
- Around line 1533-1669: The importSiteResource method may try to create
SiteVariable or SiteDeployment before their parent Site exists because calls
like $resource->getSite()->getId() (used in sites->createVariable) and
importSiteDeployment($resource) assume the Site was already created; fix by
ensuring parent Site exists before handling Resource::TYPE_SITE_VARIABLE and
Resource::TYPE_SITE_DEPLOYMENT — either enforce import ordering upstream or add
a guard in importSiteResource: check that $this->sites has the parent site (or
that $resource->getSite()->getId() resolves to a created site) and if missing,
queue the variable/deployment for retry or throw a clear, recoverable exception
so the caller can import the parent first (apply this check around the
SiteVariable handling block and before calling importSiteDeployment).
- Around line 1675-1732: The Content-Range header in importSiteDeployment is
incorrectly computing the final chunk end as getSize() instead of the inclusive
byte offset getSize() - 1; update the header construction in the client->call
('content-range' value) to use ($deployment->getEnd() == ($deployment->getSize()
- 1) ? $deployment->getSize() - 1 : $deployment->getEnd()) so the final chunk is
"bytes start-(size-1)/size" per RFC 7233; locate this change in
importSiteDeployment where the client->call headers are built (look for
'content-range' and methods getStart(), getEnd(), getSize()).
- Around line 216-223: Replace the empty strings passed to the Appwrite probe so
the SDK validation is exercised: in the block that checks Resource::TYPE_SITE,
update the call to $this->sites->create('', '', Framework::OTHER(),
BuildRuntime::STATIC1()) to use non-empty placeholder values for siteId and name
(e.g. 'test', 'test') so Sites::create() receives realistic parameters and
avoids potential SDK validation errors.

In `@src/Migration/Sources/Appwrite.php`:
- Around line 1849-1933: In exportSiteDeploymentData() the use of mb_strlen() to
determine binary download size can miscount bytes; replace mb_strlen($file) with
strlen($file) (and cast/ensure it is an int) so fileSize/size calculations and
range handling are byte-accurate for small non-chunked downloads; update the
variable set at the non-chunk branch and any comparisons that depend on it
(e.g., the $end > $size check) to use the new byte-accurate value.
- Around line 1479-1508: The exportGroupSites method currently only calls
exportSites when Resource::TYPE_SITE is requested, so requests that include
Resource::TYPE_SITE_VARIABLE but not TYPE_SITE skip exporting sites and their
variables; update the condition in exportGroupSites to call
$this->exportSites($batchSize) when either Resource::TYPE_SITE or
Resource::TYPE_SITE_VARIABLE is present, and ensure exportSites/export logic
(where site variables are collected) validates that a parent site exists before
exporting each TYPE_SITE_VARIABLE (so variables are never exported in
isolation).