test-dev: gate behind cabal flag (default off)

Adds a 'test-dev' manual cabal flag (default False) and conditionally
makes the test-dev stanza buildable only when the flag is set. Protects
against 'cabal build all --enable-tests' or 'cabal test all' picking up
the duplicate src-compile.

make live-test-dev passes -f test-dev under the hood.

Author: tonyalaribe

Makefile

@@ -44,7 +44,7 @@ live-test-reload-all:
 TEST_MATCH ?=
 live-test-dev:
 	USE_EXTERNAL_DB=true LOG_LEVEL=attention \
-	ghcid --command 'cabal repl monoscope:test:test-dev --ghc-options="-osuf dyn_o -hisuf dyn_hi -O0" --with-compiler=$(GHC)' \
+	ghcid --command 'cabal repl monoscope:test:test-dev -f test-dev --ghc-options="-osuf dyn_o -hisuf dyn_hi -O0" --with-compiler=$(GHC)' \
 		--test ':main $(if $(TEST_MATCH),--match=$(TEST_MATCH))' --warnings 2>&1 | tee build-test-dev.log
 
 hot-reload:

monoscope.cabal

@@ -135,6 +135,12 @@ custom-setup
     , base
     , proto-lens-setup
 
+flag test-dev
+  description: Build the test-dev test-suite (lib + integration as ONE GHCi target). Off by default so CI's `cabal build all` skips it; opt in for local iteration via `cabal build -f test-dev` or `make live-test-dev`.
+
+  manual: True
+  default: False
+
 library
   exposed-modules:
       BackgroundJobs
@@ -1097,6 +1103,8 @@ test-suite test-dev
     , yaml
     , zlib
   default-language: GHC2024
+  if !flag(test-dev)
+    buildable: False
 
 test-suite unit-tests
   type: exitcode-stdio-1.0

package.yaml

@@ -9,6 +9,15 @@ copyright: '2021-2026 Monoscope'
 language: GHC2024
 spec-version: 0.36.0
 
+flags:
+  test-dev:
+    description: >
+      Build the test-dev test-suite (lib + integration as ONE GHCi target).
+      Off by default so CI's `cabal build all` skips it; opt in for local
+      iteration via `cabal build -f test-dev` or `make live-test-dev`.
+    default: false
+    manual: true
+
 build-type: Custom
 custom-setup:
   dependencies:
@@ -318,9 +327,13 @@ tests:
       - vector
       - time
   # test-dev: lib + integration tests as ONE GHCi target (Jade's cabal test-dev trick).
-  # Use via `make live-test-dev`. Library deps come from hpack-includes/lib-deps.yaml
-  # (shared with `library`); integration-only extras listed inline. Not run by `make test` / CI.
+  # Gated off by default via the `test-dev` cabal flag so `cabal build all` in CI
+  # skips it. Use via `make live-test-dev` (passes -f test-dev under the hood).
+  # Library deps come from hpack-includes/lib-deps.yaml (shared with `library`).
   test-dev:
+    when:
+      - condition: '!flag(test-dev)'
+        buildable: false
     main: Main.hs
     source-dirs:
       - src