feat(source): add repo source type for AOSP/AAOS manifest-based builds

[ambient-code]

PR Description

feat(source): add repo source type for AOSP/AAOS manifest-based builds

Fixes #28

Summary

Adds repo as a first-class source type in builder-operator, enabling AOSP,
AAOS, and Cuttlefish target builds via Google's repo tool. Previously, users
had to embed repo init/repo sync inside a build stage, which prevented
operator-managed mirror reuse and re-downloaded 100+ GB of source on every build.

Changes

API types (api/v1alpha1/buildjob_types.go)

• Added SourceTypeRepo SourceType = "repo" constant
• Added RepoSource struct: manifestUrl (required), branch, manifestName,
  mirrorRef (PVC name for local mirror), syncJobs (repo sync parallelism)
• Added Repo *RepoSource field to SourceSpec
• Updated kubebuilder validation enum from Enum=git;pvc to Enum=git;pvc;repo

Deepcopy (api/v1alpha1/zz_generated.deepcopy.go)

• Added RepoSource.DeepCopyInto / RepoSource.DeepCopy
• Updated SourceSpec.DeepCopyInto to handle the new Repo pointer

Pipeline builder (internal/tekton/pipelinerun_builder.go)

• Added RepoInitImage = "python:3.12-slim" constant
• Added repo case to the source switch in BuildPipelineRunWithConfig
• Added buildRepoTaskSpec() — generates a repo-sync Tekton task:
  • Installs repo via pip if not already present
  • Runs repo init -u <url> [-b <branch>] [-m <manifest>]
  • Runs repo sync -j<N> (default 4)
  • When mirrorRef is set: mounts the named PVC read-only at /mnt/mirror
    and passes --reference=/mnt/mirror to repo init
• Updated buildEnvVars to inject BOB_MANIFEST_URL and BOB_MANIFEST_BRANCH
  when source type is repo

CRD YAML (config/crd/bases/builder.sdv.cloud.redhat.com_buildjobs.yaml)

• Updated source.type enum: [git, pvc] → [git, pvc, repo]
• Added repo object definition with all five fields

Example BuildJob

apiVersion: builder.sdv.cloud.redhat.com/v1alpha1
kind: BuildJob
metadata:
  name: aaos-cuttlefish
spec:
  toolchain:
    image: registry.example.com/aaos-host-tools:android-14
  source:
    type: repo
    repo:
      manifestUrl: https://android.googlesource.com/platform/manifest
      branch: android-14.0.0_r50
      mirrorRef: aosp-mirror
      syncJobs: 16
  target:
    board: cf_x86_64_auto
    variant: userdebug
  stages:
    - name: build
      command: |
        source build/envsetup.sh
        lunch aosp_${BOB_BOARD}-${BOB_VARIANT}
        m -j$(nproc)

Testing

• 9 new unit tests in internal/tekton/pipelinerun_builder_test.go
• All 6 test packages pass (go test ./... -race)
• go build ./... and go vet ./... pass

New tests

Test	Covers
TestBuildPipelineRun_RepoSourceTask	Basic task generation, image, script content
TestBuildPipelineRun_RepoSourceDefaultSyncJobs	Default syncJobs=4
TestBuildPipelineRun_RepoSourceMirrorMount	Mirror PVC volume+mount+--reference=
TestBuildPipelineRun_RepoSourceNoMirrorMount	No volumes when no mirrorRef
TestBuildPipelineRun_RepoSourceEnvVars	BOB_MANIFEST_URL/BRANCH injection
TestBuildPipelineRun_RepoSourceRunAfterChaining	Task ordering
TestBuildPipelineRun_RepoSourceManifestName	-m flag for manifestName
TestBuildPipelineRun_RepoSourceNoPipelineResult	No commit-sha result
TestBuildPipelineRun_RepoSourceRepoNilSkipsTask	Nil Repo spec guard

Breaking Changes

None. The Repo field is optional (omitempty). Existing git and pvc
BuildJobs are unaffected.

Reviewer Notes

• make manifests and make generate are no-ops in this project — both the
  CRD YAML and zz_generated.deepcopy.go are maintained manually. The CRD
  YAML has been updated by hand to match the new type.
• RepoInitImage = "python:3.12-slim" with runtime pip install repo works
  in connected clusters. An air-gapped follow-up (configurable image field or
  pre-baked image) is tracked separately.