fix: dev-agent worktree pushes to origin (Codeberg) instead of forgejo (local) — PR creation fails (#653)

Detect which git remote matches FORGE_URL by comparing the host portion
of FORGE_URL against remote push URLs.  Store the result in FORGE_REMOTE
(defaults to "origin" when no match — preserving existing behavior for
Codeberg-direct setups).

Replace every hardcoded "origin" in fetch, push, worktree-add, and
prompt-injection commands across:
- dev/dev-agent.sh (worktree setup, phase protocol prompt)
- dev/phase-handler.sh (CI retrigger, review feedback, rebase instructions)
- review/review-poll.sh (review feedback injection)
- action/action-agent.sh (worktree setup, push instructions)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

review/review-poll.sh

@@ -152,7 +152,7 @@ ${review_text}
 Instructions:
 1. Address each piece of feedback carefully.
 2. Run lint and tests when done.
-3. Commit your changes and push: git push origin ${pr_branch}
+3. Commit your changes and push: git push ${FORGE_REMOTE:-origin} ${pr_branch}
 4. Write: echo \"PHASE:awaiting_ci\" > \"${phase_file}\"
 5. Stop and wait for the next CI result."
   fi