feat: bake product version from Spec and expose build in health.

Resolve MAJOR.MINOR via EventHubSpec/VERSION; CI run_number as EVENTHUB_BUILD; health returns version/build/git_sha/built_at.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/handlers/admin/admin_handler_health.erl

@@ -29,7 +29,8 @@ trails() ->
             properties => #{
               status => #{type => string},
               service => #{type => string},
-              version => #{type => string},
+              version => #{type => string, description => <<"MAJOR.MINOR from EventHubSpec/VERSION">>},
+              build => #{type => integer, description => <<"CI run_number (per-repo)">>},
               git_sha => #{type => string},
               built_at => #{type => string}
             }

src/handlers/handler_health.erl

@@ -31,7 +31,8 @@ trails() ->
             properties => #{
               status => #{type => string},
               service => #{type => string},
-              version => #{type => string},
+              version => #{type => string, description => <<"MAJOR.MINOR from EventHubSpec/VERSION">>},
+              build => #{type => integer, description => <<"CI run_number (per-repo)">>},
               git_sha => #{type => string},
               built_at => #{type => string}
             }

src/infra/eventhub_build_info.erl

@@ -1,13 +1,15 @@
 -module(eventhub_build_info).
--export([info/0, version/0, git_sha/0, built_at/0]).
+-export([info/0, version/0, build/0, git_sha/0, built_at/0]).
 
 %% @doc Runtime build identity from env (baked at image build or set in compose).
+%% version = MAJOR.MINOR (EventHubSpec/VERSION); build = CI run_number (per-repo).
 -spec info() -> map().
 info() ->
   #{
     status => <<"ok">>,
     service => <<"eventhub">>,
     version => version(),
+    build => build(),
     git_sha => git_sha(),
     built_at => built_at()
   }.
@@ -15,6 +17,20 @@ info() ->
 -spec version() -> binary().
 version() -> env("EVENTHUB_VERSION", <<"0.0">>).
 
+-spec build() -> non_neg_integer().
+build() ->
+  case os:getenv("EVENTHUB_BUILD") of
+    false -> 0;
+    [] -> 0;
+    Value ->
+      try list_to_integer(Value) of
+        N when is_integer(N), N >= 0 -> N;
+        _ -> 0
+      catch
+        error:badarg -> 0
+      end
+  end.
+
 -spec git_sha() -> binary().
 git_sha() -> env("EVENTHUB_GIT_SHA", <<"unknown">>).