Delete failed lookup locations

[andrewbranch]

Failed lookup locations store the module resolution failures for every import, but we never use that granular information—we dedupe at the per-project level in the LSP to form a small set of globs to watch and then match the watch events against the deduped set to invalidate the program. That leaves potentially quite a lot of useless strings in memory. In the LSP, we were already wrapping each program's CompilerHost in a thing that tracks every requested file during construction for file cache management, making failed lookup locations and affecting locations completely superfluous.

This saves 0.8% memory on tsgo vscode/src/tsconfig.json, but 22% memory in DefinitelyTyped-tools with every workspace package open.

[andrewbranch]

Bit of a drive-by optimization since watch glob building changed to operate over already-normalized tspath.Paths

[Copilot]

Pull request overview

Reduces memory use in the language server/project system by removing per-import module-resolution “lookup locations” tracking (failed/affecting locations) and instead relying on the existing compiler-host FS wrapper that already tracks files consulted during program construction.

Changes:

• Remove FailedLookupLocations / AffectingLocations plumbing from module resolution results and resolver state.
• Simplify project watch/invalidation logic to use the compiler host’s sourceFS.seenFiles tracking instead of stored lookup-location sets.
• Update auto-import package entrypoint extraction types and adjust watch-path casing expectations in tests.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/tspath/path.go	Optimizes Path.ContainsPath to a prefix-based check for canonicalized Path values.
internal/project/watch.go	Reworks resolution-watch glob computation to take a SyncSet[tspath.Path] of seen paths.
internal/project/session_test.go	Adjusts watcher glob matching expectation for case-insensitive canonicalized paths.
internal/project/session.go	Removes updating/maintaining failed-lookup and affecting-location watches at the session level.
internal/project/projectcollectionbuilder.go	Changes invalidation logic to rebuild programs when a changed path was “seen” by the host during program construction.
internal/project/project.go	Collapses multiple project watchers into a single programFilesWatch based on sourceFS.seenFiles.
internal/module/types.go	Removes LookupLocations from resolved module/type directive results.
internal/module/resolver.go	Deletes lookup-location collection machinery; simplifies entrypoints API to return a slice directly.
internal/ls/autoimport/registry.go	Updates entrypoint handling to match the resolver API change (slice-of-entrypoints).