اضافه شدن قابلیت share و نگهداری بلندمدت

docs/PCB.md

@@ -27,7 +27,7 @@ curl -X POST https://render.sadentel.net/api/v1/pcbs/comparisons \
   -F 'access=private' -F 'expires_in=3600'
 ```
 
-Both creation requests return HTTP **202**, `Location: status_url` and `Retry-After: 1`. `access` defaults to `private`; `unlisted` is supported. Expiry is measured from admission, including queue time, and cannot exceed `LINK_TTL_SECONDS`.
+Both creation requests return HTTP **202**, `Location: status_url` and `Retry-After: 1`. `access` defaults to `private`; `unlisted` is supported. For finite links, expiry is measured from admission, including queue time, and cannot exceed `LINK_TTL_SECONDS`. Set `expires_in=-1` for unlimited retention (`expires_at: -1`); `0` and lower negative values are rejected.
 
 Example render response (identifiers, timestamps and capabilities are illustrative):
 
@@ -161,3 +161,5 @@ Real HTTP smoke checks passed against an isolated loopback Uvicorn API with SQLi
 No connected browser was available, so actual pan/pinch/menu/iframe appearance remains unverified in a browser. No trusted Altium export was supplied, so geometric and font fidelity has not been certified against Altium output.
 
 The final automated run includes native SchDoc and PCB fixtures, 154 passing Python tests and three passing frontend test files (camera, pointer interaction adapter and PCB layer policies). The standard Docker build was attempted with both normal and host networking, but dependency download stalled on `Temporary failure in name resolution` for PyPI's package host; those build attempts were stopped. A new Docker image was therefore not validated or deployed in this environment. The existing Dockerfile and dependency lock remain unchanged.
+
+Both PCB viewers and upload results include Share → Copy iframe, preserving any private read capability in the URL fragment. Unlimited jobs are excluded from automatic cleanup; external S3 lifecycle policies must also permit retention. See [expiry and embedding](API.md#unlimited-links-and-embedding).