fix: prevent canvas component loss when saving default filter

[nishantmonu51]

Root cause

CanvasEntity.saveDefaultFilters (web-common/src/features/canvas/stores/canvas-entity.ts) did a read → await → mutate → write on the canvas YAML, capturing the Document reference before the await:

1. const yaml = get(this.parsedContent) — parsedContent is a derived store over editorContent; each editorContent change emits a fresh parsed Document. The local yaml only points at one snapshot.
2. await Promise.all(...) — one queryServiceConvertExpressionToMetricsSQL round-trip per metrics view in scope (100–500 ms typical).
3. yaml.setIn(["defaults", "filters"], filterMap) then yaml.toString() then updateEditorContent(newContent, false, true) — writes the pre-await document back, immediately, via runtimeServicePutFile.

Anything that mutated editorContent during the await window was stranded on a newer Document that the saver never saw:

• Grid edits. CanvasBuilder.updateContents → updateEditorContent(..., false, true) runs saveContent immediately, not debounced. A drag/drop or resize finishing right around the click writes a newer YAML to disk.
• File-watch echo. Each save triggers FILE_EVENT_WRITE from the runtime; file-invalidators.ts re-fetches the file and, when fileUntouched, pushes the fresh blob into editorContent, re-deriving parsedContent.

When the stale YAML hit disk, the runtime reconciled a truncated canvas spec. specStore.subscribe → processSpec → processRows then deleted every component name no longer present in rows[].items[].component from the in-memory componentsStore — which is what the user perceived as "components disappeared."

The pre-existing setTimeout(100) at the top of the method is unrelated (it waits for filter-input blur) and does nothing to make the read-modify-write atomic.

Fix

• Collect pinned/time/comparison inputs and kick off Promise.all first.
• Read parsedContent after the await, then apply all mutations and write in a single synchronous block.
• clearDefaultFilters was already synchronous and is unchanged.
• Behavior on disk is unchanged for the no-concurrent-edit case: only filters.pinned and defaults.* are touched; rows/items stay byte-identical.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!

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Developed in collaboration with Claude Code