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/package.json

@@ -25,7 +25,7 @@
     "lint": "eslint src",
     "typecheck": "tsc --noEmit",
     "test": "vitest run --passWithNoTests && pnpm run test:framework-shell",
-    "test:framework-shell": "python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh"
+    "test:framework-shell": "python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh"
   },
   "dependencies": {
     "@mosaicstack/brain": "workspace:*",