fix(#812 follow-up): normalize detect-platform.sh host-match port comparison by scheme

gitea_url_matches_host compared every remote authority's port directly
against the configured HTTP(S) API URL's port, which conflated two
unrelated things and normalized default web ports asymmetrically:

- An SSH remote's transport port (e.g. ssh://git@host:2222/...) was
  compared against the configured HTTP(S) port, even though the SSH
  daemon port has nothing to do with the Gitea HTTP(S) API port.
- An explicit default port on the remote (https://host:443/...) failed
  to match an implicit (portless) configured URL, while the inverse
  (implicit remote vs. explicit configured) already matched -- the
  default-port equivalence was only applied on one side.

Fix get_remote_host() to strip an SSH transport port before it ever
reaches host-match, and make gitea_url_matches_host's default-port
normalization symmetric (":443" https / ":80" http is equivalent to
the implicit form on BOTH sides).

Adds red-first regressions for both repros to
test-pr-review-gitea-comment.sh (extending the #812 harness) and wires
that harness into packages/mosaic's test:framework-shell chain so it
runs under `pnpm test`.

Closes #850

packages/mosaic/framework/tools/git/test-pr-review-gitea-comment.sh

@@ -73,7 +73,7 @@ case "${PR_REVIEW_TEST_MODE:-}" in
     request-changes)
         [[ "$*" == "pr reject 123 --repo mosaicstack/stack --login mosaicstack" ]] || exit 91
         ;;
-    legacy-fallback|comment-success|http-success|prefix-success|subpath-success|port-success|scp-ssh-success|url-ssh-success|write-transport-failure|write-http-failure|readback-failure)
+    legacy-fallback|comment-success|http-success|prefix-success|subpath-success|port-success|scp-ssh-success|url-ssh-success|ssh-transport-port-success|explicit-default-port-success|write-transport-failure|write-http-failure|readback-failure)
         if [[ "$*" == pr\ comment* ]]; then
             # tea v0.11.1 treats the nonexistent subcommand as `tea pr list` and exits 0.
             printf '%s\n' 'INDEX TITLE STATE'
@@ -144,7 +144,7 @@ case "${PR_REVIEW_TEST_MODE:-}" in
     write-http-failure)
         write_response 500 '{"message":"simulated rejection"}'
         ;;
-    approve|request-changes|comment-success|http-success|prefix-success|subpath-success|port-success|scp-ssh-success|url-ssh-success|readback-failure)
+    approve|request-changes|comment-success|http-success|prefix-success|subpath-success|port-success|scp-ssh-success|url-ssh-success|ssh-transport-port-success|explicit-default-port-success|readback-failure)
         if [[ "$method" == "POST" && "$url" == "$PR_REVIEW_EXPECTED_API_BASE/issues/123/comments" ]]; then
             PR_REVIEW_PAYLOAD="$payload" python3 - <<'PY'
 import json
@@ -291,6 +291,23 @@ grep -q '^POST https://git.example/api/v1/repos/owner/repo/issues/123/comments$'
 run_review url-ssh-success comment durable-body https://git.example ssh://git@git.example/owner/repo.git owner/repo
 grep -q '^POST https://git.example/api/v1/repos/owner/repo/issues/123/comments$' "$CURL_LOG"
 
+# #850 (follow-up to #812): an SSH remote's transport port (e.g. `ssh://
+# git@host:2222/...`) must NOT be compared against the configured HTTP(S) API
+# URL's port -- they identify unrelated properties (SSH daemon port vs. HTTP(S)
+# provider port) of the same Gitea host. Before the fix, host-match required
+# the configured URL to carry the identical port, so this failed closed even
+# though both remote and configured URL name the same host.
+run_review ssh-transport-port-success comment durable-body https://git.example ssh://git@git.example:2222/owner/repo.git owner/repo
+grep -q '^POST https://git.example/api/v1/repos/owner/repo/issues/123/comments$' "$CURL_LOG"
+
+# #850 (follow-up to #812): an explicit default HTTP(S) port on the remote
+# (`https://host:443/...`) must be treated as equal to an implicit
+# (portless) configured URL on BOTH sides -- the pre-fix comparison only
+# normalized the default port when the REMOTE side was portless, so the
+# inverse (explicit remote, implicit configured) form failed closed.
+run_review explicit-default-port-success comment durable-body https://git.example https://git.example:443/owner/repo.git owner/repo
+grep -q '^POST https://git.example/api/v1/repos/owner/repo/issues/123/comments$' "$CURL_LOG"
+
 if run_review write-transport-failure comment durable-body; then
     echo "Expected provider transport failure to return nonzero" >&2
     exit 1