Filter file chooser by type for LinksTo/LinksToMany fields (CS-10080)

[lukemelia]

Summary

• When a LinksTo or LinksToMany field targets a specific FileDef subclass (e.g. ImageDef), the file chooser now filters the file tree to only show compatible files
• The modal title dynamically reflects the file type (e.g. "Choose Image" instead of "Choose a File")
• Passes the field's CodeRef through chooseFile() → ChooseFileModal → IndexedFileTree → fileTreeFromIndex resource, which uses it as the search filter type

Test plan

• Added acceptance test: file chooser filters by type when field is ImageDef
• Added acceptance test: file chooser shows all files when field is FileDef
• Manual test: open an edit view with an ImageDef LinksTo field, click add, verify only images appear
• Manual test: open an edit view with a FileDef LinksTo field, click add, verify all files appear

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[Copilot]

Pull request overview

Adds file-type-aware filtering and labeling to the file chooser when used from LinksTo/LinksToMany fields targeting specific FileDef subclasses (e.g. ImageDef), and covers this behavior with acceptance tests.

Changes:

• Extend chooseFile() / FileChooser API to accept optional { fileType, fileTypeName } and plumb this through the modal and indexed file tree.
• Add baseFileRef constant and use it as the default type filter for indexed file search.
• Add acceptance coverage and test-realm fixtures for ImageDef filtering vs FileDef showing all files.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/runtime-common/index.ts	Updates file chooser interface + chooseFile() helper to accept a file-type filter/name and forward to the environment chooser.
packages/runtime-common/constants.ts	Adds baseFileRef constant for FileDef code ref.
packages/base/links-to-editor.gts	Passes the field card’s CodeRef + displayName into chooseFile() for LinksTo(FileDef) fields.
packages/base/links-to-many-component.gts	Same as above for LinksToMany(FileDef) fields.
packages/host/app/components/operator-mode/choose-file-modal.gts	Accepts chooser options, updates modal title, and passes filter into IndexedFileTree.
packages/host/app/components/editor/indexed-file-tree.gts	Threads fileTypeFilter into fileTreeFromIndex(...).
packages/host/app/resources/file-tree-from-index.ts	Adds optional fileTypeFilter and uses it in the index search query (defaulting to baseFileRef).
packages/host/tests/helpers/interact-submode-setup.gts	Adds ImageLinkCard fixture and a minimal PNG file to the test realm.
packages/host/tests/acceptance/interact-submode-test.gts	Adds acceptance tests verifying filtering + modal title for ImageDef and unfiltered behavior for FileDef.
packages/experiments-realm/ImageDefPlayground/mango-demo.json	Updates demo instance JSON (appears to be fixture/data reshaping alongside this work).

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Host Test Results

    1 files  ±0      1 suites  ±0   1h 40m 14s ⏱️ -5s
1 840 tests +2  1 827 ✅ +2  13 💤 ±0  0 ❌ ±0 
1 855 runs  +2  1 842 ✅ +2  13 💤 ±0  0 ❌ ±0 

Results for commit 0bdab0c. ± Comparison against base commit d859f17.

This pull request removes 2 and adds 4 tests. Note that renamed tests count towards both.

Chrome ‑ Acceptance | interact submode tests > 1 stack: can link a file via the chooser
Chrome ‑ Acceptance | interact submode tests > 1 stack: clicking a linked file opens it as a new isolated stack item

Chrome ‑ Acceptance | file chooser tests: can link a file via the chooser
Chrome ‑ Acceptance | file chooser tests: clicking a linked file opens it as a new isolated stack item
Chrome ‑ Acceptance | file chooser tests: file chooser filters by type when field is ImageDef
Chrome ‑ Acceptance | file chooser tests: file chooser shows all files when field is FileDef

♻️ This comment has been updated with latest results.

[backspace]

I tried this locally, much easier to work with now!