filer: switch workspace upload from import-file to /workspace/import

[Sankalp-Mittal]

Changes

Replace POST /api/2.0/workspace-files/import-file/{path} with the multipart
variant of POST /api/2.0/workspace/import (via the SDK's Workspace.Upload
with format=AUTO) as the transport for all bundle file uploads. This is a
single call site: WorkspaceFilesClient.Write in libs/filer.

The error handling in Write is rewritten to branch on SDK sentinels
(errors.Is against ErrNotFound, ErrResourceAlreadyExists,
ErrAlreadyExists, ErrInvalidParameterValue, ErrPermissionDenied) instead
of raw HTTP status codes and message-substring matching. The overwrite/type-
mismatch collision is detected via the AIP-193 ErrorInfo reason
WORKSPACE_OBJECT_TYPE_MISMATCH, with a message-substring fallback for
workspaces where that detail (WP-6031) has not yet rolled out.

Why

1. /workspace-files/import-file is deprecated.
2. /workspace/import has a higher rate limit (30 vs 20 requests/sec per
   workspace) served by a dedicated RLv2 group, and is ~1.5–2× faster for a
   typical bundle deploy.
3. Structured error details let us stop parsing error message strings to detect
   path collisions.

Why multipart

/workspace/import's JSON body caps at 10 MiB for AUTO format
(databricks.webapp.autoExportFormatLimitBytes). The multipart variant accepts
the same payload sizes import-file did, so switching does not regress the
maximum uploadable file size. The 10 MiB server-side notebook cap
(databricks.notebook.maxNotebookSizeBytes) applies to both endpoints, so
maximum notebook size is unchanged.

Testserver

• libs/testserver now decodes the multipart /workspace/import body and
  mirrors the real endpoint's format=AUTO notebook detection for
  .py/.sql/.scala/.r (header comment → NOTEBOOK, otherwise FILE), and
  returns the collision error shape the CLI branches on.
• acceptance/internal/prepare_server.go records multipart bodies in a
  normalized, deterministic form (multipart_form with sorted fields; large or
  binary parts summarized) so recorded requests stay reviewable.
• The fault-injection mechanism gains an optional bodyContains match
  (fault.py --body-contains SUBSTR). Because every upload now shares the
  /workspace/import method+path, a single file's upload can only be targeted
  by its multipart path field; the two migrate/destroy fault tests rely on
  this.

Tests

• New acceptance test bundle/sync-upload-edge-cases covers the cases that
  differ between the two endpoints: a 12 MiB binary (over the JSON cap), an empty
  file, notebooks in three languages, a header-less .py (stored as FILE), a
  .lvdash.json dashboard, and non-ASCII / spaced filenames. It asserts each
  upload's object type/language and that every upload sets format=AUTO.
• Unit tests in libs/filer/workspace_files_client_test.go cover the success
  path (format/overwrite) and every error mapping (already-exists shapes,
  type-mismatch via ErrorInfo reason, 403, 500).
• libs/testserver/fault_test.go covers the new bodyContains match.
• Existing acceptance fixtures regenerated for the new request shape; the jq
  assertions in affected scripts re-aimed from .path to
  .body.multipart_form.path.

Notes

• The type-mismatch fallback (message-substring) is load-bearing until WP-6031
  is confirmed rolled out everywhere, and can be removed afterward.
• This PR does not change the sync concurrency limit.

This pull request and its description were written by Isaac.

[eng-dev-ecosystem-bot]

Integration test report

Commit: 97a20ed

Run: 30904967204

	Env	💚​RECOVERED	🙈​SKIP	✅​pass	🙈​skip	Time
💚​	aws linux	4	4	323	1065	5:26
💚​	aws windows	4	4	325	1063	11:59
💚​	azure linux	4	4	322	1065	5:58
💚​	azure windows	4	4	324	1063	11:12
💚​	gcp linux	1	5	323	1065	5:33
💚​	gcp windows	1	5	325	1063	9:17

8 interesting tests: 4 RECOVERED, 4 SKIP

	Test Name	aws linux	aws windows	azure linux	azure windows	gcp linux	gcp windows
💚​	TestAccept	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R
🙈​	TestAccept/bundle/invariant/no_drift	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/bundle/resources/vector_search_endpoints/drift/recreated_same_name	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/bundle/resources/vector_search_indexes/recreate/embedding_dimension	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
🙈​	TestAccept/ssh/connection	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S	🙈​S
💚​	TestFetchRepositoryInfoAPI_FromRepo	💚​R	💚​R	💚​R	💚​R	🙈​S	🙈​S
💚​	TestFetchRepositoryInfoAPI_FromRepo/root	💚​R	💚​R	💚​R	💚​R
💚​	TestFetchRepositoryInfoAPI_FromRepo/subdir	💚​R	💚​R	💚​R	💚​R

Top 6 slowest tests (at least 2 minutes):

duration	env	testname
8:54	aws windows	TestAccept
8:17	azure windows	TestAccept
6:24	gcp windows	TestAccept
3:07	azure linux	TestAccept
3:03	gcp linux	TestAccept
2:59	aws linux	TestAccept

[github-actions]

Approval status: pending

/acceptance/bundle/ - needs approval

77 files changed
Suggested: @denik
Also eligible: @pietern, @janniklasrose, @shreyas-goenka, @andrewnester, @anton-107, @lennartkats-db

/libs/filer/ - needs approval

Files: libs/filer/workspace_files_client.go, libs/filer/workspace_files_client_test.go
Suggested: @simonfaltum
Also eligible: @renaudhartert-db, @Divyansh-db, @hectorcast-db, @parthban-db, @tanmay-db, @tejaskochar-db, @mihaimitrea-db, @chrisst, @rauchy

General files (require maintainer)

9 files changed
Based on git history:

• @denik -- recent work in libs/testserver/, .nextchanges/bundles/, libs/filer/

_{Any maintainer (@andrewnester, @anton-107, @denik, @pietern, @shreyas-goenka, @simonfaltum, @renaudhartert-db, @janniklasrose, @lennartkats-db) can approve all areas.
See OWNERS for ownership rules.}