chore: make adversarial-review prompts base-agnostic

Addresses PR review: the prompt bodies hardcoded `git diff main...HEAD`,
which contradicted the orchestrator's parameterized `git diff $BASE...HEAD`
when run against a non-main base. The prompts now defer to the exact diff
command the orchestrator appends, and Phase 2 passes that command alongside
the findings so the refuter judges against the correct base.

Signed-off-by: phernandez <paul@basicmachines.co>

.agents/skills/adversarial-review/SKILL.md

@@ -106,7 +106,8 @@ Each model tries to refute the *other's* findings, per `prompts/refute.md`
 
 - **You** refute the other model's findings natively.
 - **The other model** refutes *your* findings — invoke it again the same way (swap
-  `prompts/review.md` for `prompts/refute.md`, append your findings JSON, and for Codex use
+  `prompts/review.md` for `prompts/refute.md`, append your findings JSON **and the
+  `git diff $BASE...HEAD` command** so it judges against the right base, and for Codex use
   `--output-schema schemas/verdicts.schema.json`).
 
 Match verdicts to findings by `id`.

.agents/skills/adversarial-review/prompts/refute.md

@@ -1,7 +1,8 @@
 # Refute the other reviewer
 
 A different reviewer (a different model family) produced the findings below against the
-same diff (`git diff main...HEAD`). Your job is to try to **refute** each one.
+same diff under review (the exact `git diff` command is provided with the findings). Your
+job is to try to **refute** each one.
 
 Default to skepticism: assume a finding is wrong until the code proves it right. A finding
 that survives a genuine attempt to disprove it is worth far more than one nobody checked.

.agents/skills/adversarial-review/prompts/review.md

@@ -3,8 +3,9 @@
 You are an independent, skeptical code reviewer. Another agent wrote this code; your
 job is to find what is actually wrong with it — not to praise it, not to rubber-stamp it.
 
-You are reviewing the diff between the merge-base of `main` and `HEAD` (i.e.
-`git diff main...HEAD`). Read the changed files in full for context, not just the hunks.
+You are reviewing a specific diff — the exact `git diff` command to run is provided at the
+end of this prompt by the orchestrator. Run it, then read the changed files in full for
+context, not just the hunks.
 
 ## What to look for, in priority order