#1356 review SF1+SF2: enumerate login-resolution suite into CI; document the tea login ladder and seat-logins.sh

SF1: test-gitea-login-resolution.sh runs 3/3 green under an empty HOME (no tea
config, no credentials, no brain), so its #1007 'resolves real credentials'
exclusion is stale. Added to ci.yml next to the other hermetic git suites and
removed from the exclusions file. Control: re-adding the exclusion line turns
check-test-enumeration.sh red (rc=1).

SF2: tools/git/README.md identity section now carries the tea-path ladder
(identity -> instance -> <instance>-<identity> login -> fail closed) and points
at tools/fleet/seat-logins.sh as the projector that provisions those logins.

packages/mosaic/framework/tools/quality/test-enumeration-exclusions.txt

@@ -13,7 +13,6 @@
 # --- tools/git: the #1007 five — non-hermetic, resolve real credentials ---
 packages/mosaic/framework/tools/git/test-pr-merge-gitea-empty-uid.sh | resolves real credentials (#1007 census); joins CI after the wrapper-half hermeticity fix (git -C scoping)
 packages/mosaic/framework/tools/git/test-issue-create-interactive-auth.sh | resolves real credentials (#1007 census); joins CI after the wrapper-half hermeticity fix
-packages/mosaic/framework/tools/git/test-gitea-login-resolution.sh | resolves real credentials (#1007 census); joins CI after the wrapper-half hermeticity fix
 packages/mosaic/framework/tools/git/test-pr-metadata-gitea.sh | resolves real credentials (#1007 census, fourth entry via family-grep); joins CI after the wrapper-half hermeticity fix
 packages/mosaic/framework/tools/git/test-issue-comment-readback.sh | resolves real credentials (#1007 census, fifth entry); joins CI after the wrapper-half hermeticity fix