feat(vault): tree search + hardened file-tree selection and read-error handling

[vutuanlinh2k2]

Summary

Reworks the vault tree panel: adds in-header search, makes file-tree selection robust across different tree renderers (incl. shadow-DOM/web-component rows and renderers that reuse a stale onSelect), stops treating directory clicks as file reads, and surfaces read failures instead of silently showing the empty state.

Closes #148

Changes

Search (feat(vault): promote search into the tree-panel header)

• New filterNodes() — case-insensitive recursive name filter. Files survive when their name matches; a directory survives whole (with all children) when its own name matches, otherwise only when some descendant survives.
• New query state drives a visibleRoot memo (empty query → full tree). The tree renders visibleRoot.
• Header's "Vault / N files" label replaced by a full-width search <input> (aria-label="Search vault", Search… placeholder, focus ring). headerActions stay on the right. countFiles() removed.

Robust selection (fix(vault): open shadow-dom tree selections)

• treeClickPath() resolves the clicked row via composedPath() (works when a shadow-DOM/web-component tree only exposes data-* attributes), falling back to closest('[data-type="item"]'). Wired through an onClickCapture handler on the scroll container.
• resolveFilePath() normalizes leading/trailing slashes against the known filePaths set; resolvedSelectedPath memo keeps the controlled/selected path canonical.
• handleTreeSelect + selectFileRef keep the select callback referentially stable while always running the latest path-validation and dirty-guard logic — fixes renderers that capture their initial onSelect and reuse it after re-render.

Directory + invalid-path handling (fix(vault): ignore directory selections)

• Clicks only open rows whose data-item-type === 'file'; directory clicks are ignored.
• A controlled selectedPath that doesn't resolve to a file is cleared (commitPath(null)) instead of being read as a file.

Read-error surfacing

• New ReadErrorState component (message + Retry), backed by readError / reloadNonce state. Read failures now show a distinct error UI rather than collapsing into the "Open a vault document" empty state.

Tests

Adds tests/vault/vault-pane.test.ts cases covering: shadow-DOM row clicks via data attributes, renderers reusing a stale selection callback, ignoring directory selections, clearing a non-file controlled path, and read-failure surfacing + retry recovery.

Notes

• Scoped to src/vault/VaultPane.tsx (+ tests). Uses existing theme tokens (border-border, text-foreground, hover:bg-muted, …).

🤖 Generated with Claude Code

[tangletools]

✅ Auto-approved PR — c3855dee

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_{tangletools · auto-approval · reason: blanket_auto_approve · 2026-06-26T14:54:05Z}