fix: accept deps: as valid conventional commit type

Automated dependency bump PRs use `deps: bump devx...` as the commit
message, but the validator rejected `deps:` as it wasn't in the allowed
types list. This caused post-merge CI failures on grm and sso-bridge.

Implements: DEVX-165

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

docs/specs/DEVX-165.md

@@ -0,0 +1,31 @@
+# DEVX-165: Accept deps: as valid conventional commit type
+
+## Problem
+The commit validator rejects `deps:` as a conventional commit type, causing
+post-merge CI failures on grm and sso-bridge repos where automated dependency
+bump PRs use `deps: bump devx...` as the commit message.
+
+## Approach
+REQ-1: Add `deps` to `CONVENTIONAL_RE` in `src/devx/config.py`
+REQ-2: Update the allowed types list in the error message in
+  `src/devx/ci/validate_commit_msg.py`
+REQ-3: Add test coverage for `deps:` type in `tests/unit/test_config.py`
+  and `tests/unit/test_validate_commit_msg.py`
+
+## Test Plan
+- `make pytest-cov` passes with 100% coverage
+- `make lint-all` passes
+
+## Deploy Plan
+- Merge to master → post-merge auto-publishes new devx version
+- grm and sso-bridge bump devx version to pick up the fix
+
+## Rollback Plan
+- Revert the merge commit
+
+## Acceptance Criteria
+- [x] REQ-1: Add `deps` to `CONVENTIONAL_RE` in `src/devx/config.py`
+- [x] REQ-2: Update the allowed types list in the error message in
+  `src/devx/ci/validate_commit_msg.py`
+- [x] REQ-3: Add test coverage for `deps:` type in `tests/unit/test_config.py`
+  and `tests/unit/test_validate_commit_msg.py`