refactor: group internal non-product targets under Sources/_support/

Package.swift

@@ -49,7 +49,7 @@ let package = Package(
         // compile for both wasm and the host compiler plugin.
         .target(
             name: "SwiflowCSSCore",
-            path: "Sources/SwiflowCSSCore",
+            path: "Sources/_support/SwiflowCSSCore",
             swiftSettings: [.swiftLanguageMode(.v6)]
         ),
         .macro(
@@ -115,7 +115,7 @@ let package = Package(
         // re-implement it inline because they couldn't import an executable).
         .target(
             name: "SwiflowEmbedders",
-            path: "Sources/SwiflowEmbedders",
+            path: "Sources/_support/SwiflowEmbedders",
             swiftSettings: [.swiftLanguageMode(.v6)]
         ),
         // Repo-dev codegen tool: `swift run swiflow-codegen <driver|templates|all>`.
@@ -235,7 +235,7 @@ let package = Package(
         .target(
             name: "MacroConsumerChecks",
             dependencies: ["Swiflow", "SwiflowQuery", "SwiflowStore"],
-            path: "Sources/MacroConsumerChecks",
+            path: "Sources/_support/MacroConsumerChecks",
             swiftSettings: [.swiftLanguageMode(.v6)]
         ),
         .testTarget(

Sources/MacroConsumerChecks/ComponentChecks+Styles.swift → Sources/_support/MacroConsumerChecks/ComponentChecks+Styles.swift

@@ -1,5 +1,3 @@
-// Sources/MacroConsumerChecks/ComponentChecks+Styles.swift
-//
 // The documented scopedStyles-in-extension pattern: @Component's
 // memberAttribute role can't reach extension members, so the explicit
 // @MainActor here is required — this file pins that the pattern keeps

Sources/MacroConsumerChecks/ComponentChecks.swift → Sources/_support/MacroConsumerChecks/ComponentChecks.swift

@@ -1,5 +1,3 @@
-// Sources/MacroConsumerChecks/ComponentChecks.swift
-//
 // COMPILE-ONLY GATE for the component-side macros.
 // `assertMacroExpansion` type-checks nothing, and the compile gates that DO
 // live inside test targets (BareComponentIsolationTests & friends) use

Sources/MacroConsumerChecks/PersistedChecks.swift → Sources/_support/MacroConsumerChecks/PersistedChecks.swift

@@ -1,5 +1,3 @@
-// Sources/MacroConsumerChecks/PersistedChecks.swift
-//
 // COMPILE-ONLY GATE for @Persisted. Consumes the macro
 // the way a real app does: PLAIN imports, a public @Component, public
 // @Persisted members read from a main-actor body.

Sources/MacroConsumerChecks/QueryMutationChecks.swift → Sources/_support/MacroConsumerChecks/QueryMutationChecks.swift

@@ -1,5 +1,3 @@
-// Sources/MacroConsumerChecks/QueryMutationChecks.swift
-//
 // COMPILE-ONLY GATE for @Query/@Mutation witness isolation.
 // MainActorWitnessIsolation.witnessNames = ["fetch", "perform",
 // "optimistic", "invalidations"] is hand-encoded string policy that must

Sources/SwiflowCSSCore/CSSScopeRules.swift → Sources/_support/SwiflowCSSCore/CSSScopeRules.swift

@@ -1,5 +1,3 @@
-// Sources/SwiflowCSSCore/CSSScopeRules.swift
-//
 // The single source of truth for which CSS selectors escape component scoping.
 // Shared by BOTH scope-deciding paths so they can never drift:
 //   - the runtime CSS DSL (`Swiflow.CSSSheet.scopedSelector`, wasm)

Sources/SwiflowEmbedders/DriverEmbedder.swift → Sources/_support/SwiflowEmbedders/DriverEmbedder.swift

@@ -1,5 +1,3 @@
-// Sources/SwiflowEmbedders/DriverEmbedder.swift
-//
 // THE emit path for EmbeddedDriver.swift — invoked by the swiflow-codegen
 // tool (`swift run swiflow-codegen driver`), which replaced the standalone
 // script that used to re-implement this inline. The byte-pin test in

Sources/SwiflowEmbedders/RuntimeCopySync.swift → Sources/_support/SwiflowEmbedders/RuntimeCopySync.swift

@@ -1,5 +1,3 @@
-// Sources/SwiflowEmbedders/RuntimeCopySync.swift
-//
 // The generated runtime JS lives canonically in js-driver/ and as tracked
 // per-example copies (7× swiflow-driver.js, 9× swiflow-service-worker.js,
 // plus RegionDemo's regions pair). Those copies used to be refreshed by

Sources/SwiflowEmbedders/TemplateEmbedder.swift → Sources/_support/SwiflowEmbedders/TemplateEmbedder.swift

@@ -1,5 +1,3 @@
-// Sources/SwiflowEmbedders/TemplateEmbedder.swift
-//
 // THE emit path for EmbeddedTemplates.swift — invoked by the swiflow-codegen
 // tool (`swift run swiflow-codegen templates`), which replaced the standalone
 // script that used to duplicate this logic, and byte-pinned by the freshness