ci: pin grpcio-tools==1.81.1 + regenerate stubs to fix proto stub drift

The 'proto stub drift' CI job (and thus the README CI badge on main) was red
because grpcio-tools was installed from a loose range (>=1.65,<2.0) in both
requirements.txt and ci.yaml. The range floated from 1.81.0 (when the stubs
were committed) up to 1.81.1, and the generated stub embeds the generator
version as GRPC_GENERATED_VERSION, so regeneration produced a one-line diff
(1.81.0 -> 1.81.1) that failed the byte-identical drift gate.

Fix (durable): pin grpcio-tools to the EXACT version in both places and
regenerate the committed stub so it matches. Future generator bumps now
require a deliberate pin change.

- requirements.txt: grpcio-tools>=1.65,<2.0 -> ==1.81.1 (+ rationale comment)
- .github/workflows/ci.yaml: install grpcio-tools==1.81.1 (+ rationale comment)
- runtime_pb2_grpc.py: GRPC_GENERATED_VERSION 1.81.0 -> 1.81.1 (regenerated)

Verified locally: drift check (git diff --exit-code after regenerate) PASSES;
proto stubs import OK.

Co-authored-by: FluffyAIcode <FluffyAIcode@users.noreply.github.com>

Author: cursoragent

.github/workflows/ci.yaml

@@ -267,11 +267,12 @@ jobs:
       - name: Install grpcio-tools
         run: |
           python -m pip install --upgrade pip
-          # Pin the same grpcio-tools range as requirements.txt so the
-          # stubs we regenerate match what production uses. If
-          # grpcio-tools updates and starts producing different stub
-          # bytes, this job catches it as a drift before merge.
-          pip install 'grpcio>=1.65,<2.0' 'grpcio-tools>=1.65,<2.0'
+          # Pin grpcio-tools to the EXACT version in requirements.txt. The
+          # generated stub embeds the generator version
+          # (GRPC_GENERATED_VERSION), so a loose range lets a patch release
+          # float (e.g. 1.81.0 -> 1.81.1) and fail this drift gate on a
+          # version string alone. Keep this in lockstep with requirements.txt.
+          pip install 'grpcio>=1.65,<2.0' 'grpcio-tools==1.81.1'
 
       - name: Set up Node.js (for ts-proto plugin)
         uses: actions/setup-node@v4

inference_engine/server/proto_gen/kakeya/v1/runtime_pb2_grpc.py

@@ -5,7 +5,7 @@
 
 from . import runtime_pb2 as kakeya_dot_v1_dot_runtime__pb2
 
-GRPC_GENERATED_VERSION = '1.81.0'
+GRPC_GENERATED_VERSION = '1.81.1'
 GRPC_VERSION = grpc.__version__
 _version_not_supported = False
 

requirements.txt

@@ -51,8 +51,14 @@ prometheus-client>=0.20,<1.0
 # file because (a) we want CI to be able to drift-check the
 # committed stubs, and (b) the install footprint is small and there
 # is no separate dev-requirements file in this project today.
+#
+# grpcio-tools is PINNED to an EXACT version: the generated stub embeds
+# the generator version as `GRPC_GENERATED_VERSION = '<grpcio-tools ver>'`,
+# so a loose range lets a patch release (e.g. 1.81.0 -> 1.81.1) silently
+# change the committed bytes and fail the `proto stub drift` CI gate.
+# Bump this pin (and re-run scripts/regenerate_proto_stubs.sh) deliberately.
 grpcio>=1.65,<2.0
-grpcio-tools>=1.65,<2.0
+grpcio-tools==1.81.1
 
 # K2.A KakeyaLattice K/V cache compression (ADR 0008 §11.11).
 # Pinned to >= 1.5 (the tested Mac M4 release; see PR-K2.A.0