Warn when companion extensions are too old for inline-script envs - #1777

…nments (#1780)

> Part of #1602. Design: #1601. Follow-up to #1772.

## Summary

Fix PEP 723 inline-script cache and routing issues, make cached
environments read-only through the package-management UI, and support
deleting one cached environment without clearing the entire script
cache.

The feature remains behind the internal, undeclared
`python-envs.inlineScripts.enabled` flag, which defaults to `false` and
is latched at activation. This does not enable inline scripts by default
or add automatic installation on Run/Debug.

## Commits and user-visible changes

| Commit | Problem or missing behavior | Change |
|---|---|---|
| `64960273` | The first package enumeration could be mistaken for an
installation, so expanding Packages or refreshing inventory invalidated
a working script environment. Case-only Windows renames could also lose
the association. | Replace package-event-based drift detection with a
recorded inventory hash; hide package mutation actions and reject the
palette install path for inline environments; preserve Windows case-only
rename associations, including dirty aliases and pending reads. |
| `669ffe18` | A lookup could detect drift and return no environment
while routing still advertised the cache as valid and the setup CodeLens
remained hidden. Other scripts sharing the entry could retain stale
state. | Confirm drift against the current entry, invalidate affected
routing/cached validation, and notify environment consumers without
requiring a save. Protect newer repairs and selections from stale
observations. |
| `1d3ea92a` | Delete Environment was offered in the Projects view, but
the inline manager did not implement removal and returned "Remove
Environment not supported". | Delete the selected cache entry without a
confirmation dialog, clear its known workspace associations, and update
the environment collection. Preserve script files, project
entries/settings, the base interpreter, and unrelated cache entries. |

## Implementation and behavior notes

### Record package inventory instead of interpreting package events

- When inventory is readable, setup records an `installedPackagesHash`
in the entry's `.meta.json`, under the existing cache-entry lock. The
hash is computed from sorted, case-normalized `*.dist-info` names, which
include distribution names and versions.
- Validation and reuse compare the recorded inventory with disk. Merely
expanding or refreshing the package list no longer has authority to
invalidate the environment.
- A missing baseline or unreadable inventory is **unknown**, not
evidence that packages were added. Existing `manuallyModified` sidecars
remain honored.
- The package list stays visible, but inline environments do not offer
Install, Uninstall, or Change Version actions in the trees. The palette
install command explains that dependencies should be edited in the
script's metadata and setup rerun.
- No new package-provider event metadata, per-package operation queues,
or provider opt-in interfaces are introduced. The pip, Conda, Poetry,
shared package-change helper, and package-watcher implementations are
unchanged.

### Keep routing and the setup action consistent

- A confirmed mismatch clears the affected scripts' cached environments
and validation state, advances revisions, restores their setup
CodeLenses, and publishes environment changes.
- Invalidation rechecks the current sidecar/inventory under a
non-waiting cache-entry lock. An observation made before a repair must
not invalidate the repaired entry.
- Busy entries and unavailable confirmation reads do not publish stale
invalidations. A newer selection wins when an older lookup finishes
later.
- Detection is on demand, after the existing five-second validation
cache expires; this is not a new background polling service.

### Delete one cached environment

- Delete means physical deletion whether the entry has one associated
script or several. It is not silently changed into "detach this script"
for shared entries.
- The action has **no confirmation dialog**. Scripts sharing the deleted
entry need setup again.
- Reuse the existing cache maintenance, ownership/path checks, locks,
and association-cleanup machinery, with a single-entry target. Do not
invoke the bulk project-settings cleanup.
- Route an inline Projects-view item through the manager owning the
clicked environment, rather than the file's potentially changed fallback
manager. Ordinary environment removal keeps its existing routing.
- Reject missing arguments, foreign/out-of-cache targets, redirected
entries, and active creation conflicts. Preserve unrelated and
unrecognized association records.
- Invalidate a valid sidecar before filesystem removal so an interrupted
deletion does not leave surviving cache files trusted as healthy. Report
filesystem/persistence failures and update local state for what was
actually removed.

## Testing

Local validation before the rebase/signing update (`1afe4bc9`):

- `npm run compile-tests`: passed.
- `npm run compile` (webpack extension bundle): passed.
- `npm run lint`: passed.
- Full unit suite: **2,074 passing, 6 pending**.

Coverage includes get-only drift detection and CodeLens recovery, shared
versus unrelated entries, stale observations after newer
repairs/selections, real cache-entry locks, unavailable inventory,
Windows case-only renames, palette restrictions, targeted deletion
without prompting, protected source/settings/base-Python files,
already-missing entries, unsafe paths, partial failures, and concurrent
create/delete/rehydration.

### Suggested manual verification

These are reviewer checks, not a claim that a full live VS Code
end-to-end pass has been completed:

1. Enable `python-envs.inlineScripts.enabled` and reload. Use the Python
Environments integration and companion builds that support per-file
interpreters.
2. Set up two scripts with the same metadata so they share a cached
environment, plus a third script using a different cache entry.
3. Expand/refresh Packages: setup remains valid and inline package
mutation actions are absent. The palette install action for an inline
project should show guidance rather than install.
4. In a disposable test environment, change installed packages
externally. After the validation cache expires, request the script's
environment without saving. Verify the affected setup actions return and
explicit setup repairs the entry.
5. On Windows, rename `job.py` to `Job.py`; verify the existing
environment remains associated and unsaved metadata is not replaced with
stale disk metadata.
6. Delete a shared inline environment from the Projects view. Verify
there is no confirmation, only that cache entry is deleted, affected
scripts need setup again, and the unrelated environment, scripts,
project settings, and base Python remain.
7. Exercise a busy/failed deletion and verify it reports failure rather
than success. Recheck normal package management/removal for an ordinary
venv.

## Scope and known follow-ups

- Inventory comparison is not a full package-integrity audit: it does
not inspect package contents or legacy `.egg-info`-only installations.
- Shared cache entries can be referenced by other workspaces.
Association cleanup/notifications here are local to the current
workspace; other windows notice deletion on revalidation. Cache locks do
not track arbitrary running Python processes, so running jobs should be
stopped before deletion.
- The current unknown-inventory behavior is retained. The case where an
entirely missing `site-packages` directory is accepted during reuse
remains a follow-up; deleting the cache entry and running setup provides
a recovery path.
- A rejected inline selection can still briefly show the temporary
"selected" badge; the actual selection is not changed. That feedback fix
is separate from the routing invalidation addressed here.
- Companion-version guidance is covered separately by #1777. No
installer-backend, retention-policy, or Run/Debug auto-setup changes are
included.

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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: a4277008-9dd3-4beb-b9ac-4197eb085404