Enable manual CI runs via workflow_dispatch (#81)

* Enable manual CI runs via workflow_dispatch

Adds the "Run workflow" button on the Actions tab so CI can be triggered
manually against a branch.

* Route uv through the Databricks pypi proxy in CI

The databricks-protected-runner-group blocks direct egress to pypi.org
(TLS handshake EOF when fetching setuptools to build thrift from sdist).
Point UV_INDEX_URL at the internal mirror so installs go through the
allowed proxy.

Author: rohita5l

.github/workflows/ci.yml

@@ -1,6 +1,7 @@
 name: CI
 
 on:
+  workflow_dispatch:
   pull_request:
   push:
     branches: [main]
@@ -13,6 +14,8 @@ jobs:
     runs-on:
       group: databricks-protected-runner-group
       labels: linux-ubuntu-latest
+    env:
+      UV_INDEX_URL: https://pypi.proxy.cloud.databricks.com/simple
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
       - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b  # v8.1.0
@@ -24,6 +27,7 @@ jobs:
       group: databricks-protected-runner-group
       labels: linux-ubuntu-latest
     env:
+      UV_INDEX_URL: https://pypi.proxy.cloud.databricks.com/simple
       UCODE_TEST_WORKSPACE: ${{ secrets.UCODE_TEST_WORKSPACE }}
       DATABRICKS_HOST: ${{ secrets.UCODE_TEST_WORKSPACE }}
       DATABRICKS_CLIENT_ID: ${{ secrets.DATABRICKS_CLIENT_ID }}