Fix install/clone instructions to point at our fork, revert max-version to 35

README.md and install.sh's install instructions still told new users to
git clone the abandoned upstream (fanategorius/occweb), which lacks all
of this fork's fixes. Point those at dillardblom/occweb; leave the
Credits section's links to Adphi/fanategorius as-is since those are
deliberate attribution, not install instructions. Also repoint the
README screenshot badge, which was hotlinking Adphi's repo.

composer.json still listed only the original author; add ourselves
alongside, matching the info.xml author field.

Revert max-version 40->35: 35 was fanategorius's own tested release
value (commit 7c09dd2), not a guess. Bumping to 40 was our own
speculative headroom into an untested future major - exactly the
pattern this project's own history already reverted twice, for the
same stated reason ("hasn't been tested against newer Nextcloud
releases"). Getting auto-disabled by the compat check on an untested
major is the correct, safe failure mode; claiming compatibility we
haven't verified is not. 35 still satisfies the Codex finding (no
narrowing below a previously-validated ceiling) without guessing ahead.

composer.json

@@ -6,6 +6,10 @@
     "authors": [
         {
             "name": "Adphi"
+        },
+        {
+            "name": "Dillard Blom",
+            "email": "dillard.blom@ensembia.com"
         }
     ],
     "require": {},