feat(whaleflow): add typed workflow foundation

CHANGELOG.md

@@ -33,6 +33,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   grounded objectives, context, sources, critical files, constraints,
   verification, risks, and handoff notes through the transcript card, Plan
   confirmation prompt, `/relay`, fork-state, and saved-session replay.
+- Added the first `codewhale-whaleflow` foundation crate with typed workflow
+  config/IR validation and deterministic phase ordering tests. This preserves
+  the WhaleFlow direction from #2482/#2486 without exposing a runtime
+  `workflow_run` tool until cancellation, replay, and worktree semantics are
+  release-safe. Thanks @AdityaVG13 for the WhaleFlow draft and cost-tracking
+  direction.
 - Added `POST /v1/sessions` for runtime clients to save a completed thread as a
   managed session. The endpoint preserves thread title/model/mode/workspace
   metadata, maps missing threads to 404, and returns 409 instead of snapshotting

Cargo.toml

@@ -15,6 +15,7 @@ members = [
     "crates/tools",
     "crates/tui",
     "crates/tui-core",
+    "crates/whaleflow",
 ]
 default-members = ["crates/cli", "crates/app-server", "crates/tui"]
 resolver = "2"

crates/tui/CHANGELOG.md

@@ -33,6 +33,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   grounded objectives, context, sources, critical files, constraints,
   verification, risks, and handoff notes through the transcript card, Plan
   confirmation prompt, `/relay`, fork-state, and saved-session replay.
+- Added the first `codewhale-whaleflow` foundation crate with typed workflow
+  config/IR validation and deterministic phase ordering tests. This preserves
+  the WhaleFlow direction from #2482/#2486 without exposing a runtime
+  `workflow_run` tool until cancellation, replay, and worktree semantics are
+  release-safe. Thanks @AdityaVG13 for the WhaleFlow draft and cost-tracking
+  direction.
 - Added `POST /v1/sessions` for runtime clients to save a completed thread as a
   managed session. The endpoint preserves thread title/model/mode/workspace
   metadata, maps missing threads to 404, and returns 409 instead of snapshotting

crates/whaleflow/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "codewhale-whaleflow"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+description = "Typed WhaleFlow workflow IR and validation for CodeWhale"
+
+[dependencies]
+serde.workspace = true
+thiserror.workspace = true
+
+[dev-dependencies]
+serde_json.workspace = true