air run: package code_source tarball via DABs artifact upload

[vinchenzo-db]

Package the code_source working tree into a tarball and upload it through DABs' artifact-upload plumbing (libraries.ReplaceWithRemotePath + libraries.Upload over a minimal in-memory bundle), rewriting ai_runtime_task.code_source_path to the uploaded remote path. The packaging + upload orchestration is CLI-owned (experimental/air/cmd, OWNERS = us); it only reuses DABs' uploader so we don't reimplement workspace/volume upload.

snapshot_dabs.go: build the plain-tar tarball (createPlainTarball), carry it as a file-valued code_source_path on a minimal bundle, and drive the DABs upload. runsubmit.go swaps the old raw-filer snapshot upload for this. Removes the retired raw-filer upload path (snapshot.go uploader, snapshot_test.go).

Tar snapshotting only; git pinning follows in the next PR (its git helpers are removed here and reintroduced there).

Co-authored-by: Isaac

Changes

Why

Tests

# v.chen at ip-10-90-29-234 in ~/databricks-cli (git:air-cli-git-pinning) [19:09:56]
$ cd /home/v.chen/databricks-cli
go build -o /tmp/dbcli-air ./main.go
# v.chen at ip-10-90-29-234 in ~/databricks-cli (git:air-cli-git-pinning) [19:10:32]
$ rm -rf /tmp/air-e2e && mkdir -p /tmp/air-e2e/src
cat > /tmp/air-e2e/src/train.py <<'PY'
import os
print("cwd:", os.getcwd(), "CODE_SOURCE_PATH:", os.environ.get("CODE_SOURCE_PATH"))
PY
cat > /tmp/air-e2e/train.yaml <<'YAML'
experiment_name: vchen_clistack_e2e
command: cd $CODE_SOURCE_PATH && python train.py
compute:
  accelerator_type: GPU_1xA10
  num_accelerators: 1
environment:
  version: "4"
  dependencies: []
code_source:
  type: snapshot
  snapshot:
    root_path: src
YAML
# v.chen at ip-10-90-29-234 in ~/databricks-cli (git:air-cli-git-pinning) [19:10:41]
$ cd /tmp/air-e2e
/tmp/dbcli-air experimental air run -f train.yaml -p dbc-04ac0685-8857
Uploading src.tar.gz...
Submitted run 282829443240803
View at: https://dbc-04ac0685-8857.staging.cloud.databricks.com/jobs/runs/282829443240803
# v.chen at ip-10-90-29-234 in /tmp/air-e2e (git:) [19:10:58]
$ /tmp/dbcli-air workspace list /Workspace/Users/v.chen@databricks.com/.air/repo_snapshots/.internal -p dbc-04ac0685-8857
ID                Type  Language  Path
4370802146211389  FILE            /Workspace/Users/v.chen@databricks.com/.air/repo_snapshots/.internal/src.tar.gz
# v.chen at ip-10-90-29-234 in /tmp/air-e2e (git:) [19:15:46]
$ /tmp/dbcli-air experimental air get 282829443240803 -p dbc-04ac0685-8857

╭─ Configuration ────────────────────────────────────────────────╮
│                                                                │
│  experiment_name: vchen_clistack_e2e                           │
│  command: cd $CODE_SOURCE_PATH && python train.py              │
│  compute:                                                      │
│    accelerator_type: GPU_1xA10                                 │
│    num_accelerators: 1                                         │
│  environment:                                                  │
│    version: "4"                                                │
│    dependencies: []                                            │
│  code_source:                                                  │
│    type: snapshot                                              │
│    snapshot:                                                   │
│      root_path: src                                            │
│                                                                │
╰────────────────────────────────────────────────────────────────╯

╭─ Metadata ─────────────────────────────────────────────────────╮
│                                                                │
│  Run ID        282829443240803                                 │
│  Status        ● SUCCESS                                       │
│  Submitted     2026-07-21 19:10 UTC                            │
│  Retries       0                                               │
│  Max Retries   0                                               │
│  Duration      1m 22s                                          │
│  Experiment    vchen_clistack_e2e                              │
│  MLflow Run    vchen_clistack_e2e-350226244858021              │
│  User          v.chen@databricks.com                           │
│  Accelerators  1x A10                                          │
│  Environment   N/A                                             │
│                                                                │
╰────────────────────────────────────────────────────────────────╯

Run URL:    https://dbc-04ac0685-8857.staging.cloud.databricks.com/jobs/runs/282829443240803?o=3360802220363900
MLflow URL: https://dbc-04ac0685-8857.staging.cloud.databricks.com/ml/experiments/4370802146211390/runs/6e7fcbb599764aab8fd1f0a050ca6860
# v.chen at ip-10-90-29-234 in /tmp/air-e2e (git:) [19:16:29]
$ 

[github-actions]

Waiting for approval

Based on git history, these people are best suited to review:

• @riddhibhagwat-db -- recent work in experimental/air/cmd/

Eligible reviewers: @apeforest, @ben-hansen-db, @bfontain, @lu-wang-dl, @maggiewang-db, @panchalhp-db, @pardis-beikzadeh-db

_{Suggestions based on git history. See OWNERS for ownership rules.}