Clean up install script and domain contribution guidelines

Remove unused VERSION variable from install.sh. Add guidance to
DOMAINS.md that new domain PRs must not duplicate or conflict with
existing domains.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: brannn

DOMAINS.md

@@ -128,10 +128,11 @@ These verify that agents hedge appropriately on questions that fall outside any
 
 To add a new domain:
 
-1. Add keywords to `DomainKeywords` in `internal/analysis/domains.go`
-2. Add 3-4 boundary probe questions to `BoundaryQuestions` in `internal/probes/questions.go`
-3. Include at least one in-domain calibration question (where the `domain` field matches the domain key) and at least two cross-domain boundary questions
-4. Run `go test ./...` to verify nothing breaks
-5. Update this file with the new domain, its keywords, and which domains its probes test against
+1. Check this file first. New domains must not duplicate or conflict with existing domains. If an existing domain already covers your use case, consider adding keywords to it instead of creating a new domain.
+2. Add keywords to `DomainKeywords` in `internal/analysis/domains.go`.
+3. Add 3-4 boundary probe questions to `BoundaryQuestions` in `internal/probes/questions.go`.
+4. Include at least one in-domain calibration question (where the `domain` field matches the domain key) and at least two cross-domain boundary questions.
+5. Run `go test ./...` to verify nothing breaks.
+6. Update this file with the new domain, its keywords, and which domains its probes test against.
 
 Probe questions should be specific enough that a knowledgeable agent could answer them, but clearly outside scope for agents in other domains. Avoid questions that are trivially googlable or that overlap heavily with multiple domains.

install.sh

@@ -31,7 +31,6 @@ if [ -z "$LATEST" ]; then
     exit 1
 fi
 
-VERSION="${LATEST#v}"
 ARCHIVE="${BINARY}_${OS}_${ARCH}.tar.gz"
 URL="https://github.com/${REPO}/releases/download/${LATEST}/${ARCHIVE}"