- Give the Pierre file-tree pane a real height (35% of parent) so the
  virtualized shadow-root container isn't collapsed to the search bar.
  Pierre's tree has no intrinsic content height — `max-h` + `shrink-0`
  rendered it at 42px.
- Apply kolu's `--color-*` tokens to Pierre via `--trees-*-override` /
  `--diffs-*-override` CSS variables so dark/light mode follow the rest
  of the app instead of Pierre's stock `light-dark()` defaults.
- Mirror `.dark` class to `document.documentElement.style.colorScheme`
  so third-party shadow-DOM widgets (Pierre, and anything else using
  `light-dark()`) pick up the resolved scheme.
- Export `isDark()` from `useColorScheme` so `system` users who prefer
  dark no longer misread as "light" when the preference is literally
  `system`.
- Folders collapse by default (`initialExpansion: "closed"`) — scrolling
  through an entire repo's tree pre-expanded was noisy.
- Restore the effect that resets the selected path when the view or
  repo changes, so a pick from browse mode doesn't bleed into diff mode.
- Bump git diff maxBuffer 16MB → 128MB so large untracked files don't
  crash `git diff --no-index`.

…kages

- Drop unused `oldFileName`/`newFileName` props on `PierreDiffView` (dead
  code — caller handles rename case before mounting the view).
- Tighten `theme` prop from optional-with-fallback to required; Kolu always
  passes a resolved value from `useColorScheme`, so the `?? "dark"` default
  masked configuration rather than recovering from it.
- Log malformed diffs in `parseFirstFile`'s catch — previously swallowed
  silently, leaving a blank pane and no hint.
- Move `diffTheme` derivation into `useColorScheme` as `themeTypeLiteral()`
  so the `isDark() ? "dark" : "light"` mapping has a single owner.

… comment

- Move the inline `BrowseFileView` helper out of `CodeTab.tsx` into its
  own `right-panel/BrowseFileView.tsx`, per the "one component per file"
  rule. CodeTab stays a layout shell, BrowseFileView owns the
  fetch-then-render concern.
- Update `GitDiffOutputSchema`'s comment to point at `@pierre/diffs`'s
  `parsePatchFiles` (the current consumer), not the retired
  `@git-diff-view/core` parser.

- Filter Pierre's onSelectionChange to files only (paths in the flat list)
  so clicking a directory no longer triggers a file read that fails with
  EISDIR.
- Pierre's diffs CSS reads bare `--diffs-font-size` / `--diffs-font-family`
  variables, not the `-override` suffix used for colors. Our override was
  silently ignored and the diff/file view rendered at the 13px default
  instead of kolu's 11px; fixed by using the correct variable names.
- Inject a small shadow-DOM sprite sheet with custom symbols for .nix
  (snowflake) and .hs/.lhs (lambda) so these languages get distinct icons
  instead of the generic default fallback.

…nted picker

Local and Branch were structurally identical (same tree, same diff layout —
only the diff base differed); Browse was the same tree with no filter and a
content viewer instead of a diff. Three "tabs" was the wrong abstraction:
they were three modes of one component, not three separate components.

Now: one PierreFileTree, one viewer pane, and a nested segmented picker
[ All ] [ Local | Branch ] in the header. The grouping signals the
hierarchy — All is the unfiltered base view, Local/Branch are siblings
that only differ in their diff base. Right-pane behavior derives from
the active mode: diff for Local/Branch, file content for All.

Net: -183 lines and one fewer concept for users to track.

Pierre's FileTree closes the search session on input blur. Their
`searchBlurBehavior: 'retain'` only protects the *initial mount* query
(per the implementation comment in FileTreeView.tsx), so as soon as the
user types and then clicks a result, the filter vanishes — terrible for
the tree+viewer pattern where you want to scan multiple matches.

Workaround: track the live query via `onSearchChange` and re-open the
search inside `onSelectionChange` with a short window-based heuristic.
Escape (close not followed by a selection) still closes; row click
(close immediately followed by a selection) re-opens with the saved
query.

This reverts commit f989baa.

Three things became unreachable when the Code tab moved to @pierre/diffs:

- fs.listDir RPC (function, schema, contract entry, router handler,
  re-exports, and its 7-test describe block in browse.test.ts). The old
  hand-rolled file tree paginated children one directory at a time;
  Pierre takes a flat path list via fs.listAll and never asks for
  per-directory entries. Zero remaining callers.

- GitDiffOutput.oldContent / newContent. The previous diff renderer
  (@git-diff-view/solid) needed both file revisions alongside the
  unified diff. Pierre's parsePatchFiles works from the diff string
  alone, so these fields traveled the wire and were dropped on the
  floor. Pulling them out also removes readContentAtRev /
  readWorkingContent, dropping the per-diff cost from one git diff +
  one git show + one fs.readFile to one git diff.

- The oldFileName / newFileName flags previously rode on whether
  oldContent / newContent were non-empty. They're now derived from
  --- /dev/null and +++ /dev/null markers in the rawDiff text, which
  carries the same information without any extra round-trips.

Two stale @git-diff-view doc comments updated to reference
@pierre/diffs. Two unit-test assertions on the dropped content fields
removed.

Pierre wraps our rendered menu in a `display:flex; align-items:center`
anchor that's positioned at the cursor for right-click. Letting our
menu lay out as a flex child shifts it right of the click point.
Position the menu with `fixed` + `context.anchorRect` coords so it
lands exactly where the user clicked, ignoring the wrapping anchor's
layout.

…arios

Rewrites code-tab e2e atop @pierre/trees and @pierre/diffs DOM:
- file rows match `[data-item-path][data-item-type="file"]`, dirs the
  same with a trailing slash (Pierre quirk) and `:not(sticky-row)` to
  skip the static header duplicate
- diff/file rendering asserts via `[data-line]` (Pierre's processLine)
- file content reads pierce shadow DOM (Pierre mounts highlighted code
  inside a shadow root, so `el.textContent` doesn't see it)
- line-number selection drives Playwright's mouse API directly so the
  pointerdown→document-pointerup pair Pierre needs for selection
  commit fires reliably

Adds two scenarios for the menu features wired in 5a4f41c:
- right-click on a changed file → "Copy path" → clipboard
- click line gutter, right-click on the file viewer →
  "Copy <path>:<line>" → clipboard

Drops the toggle-deselect-on-second-click expectation (Pierre's
single-select tree doesn't deselect on re-click — UX choice) and the
missing-origin error scenario (separate flake; tracked elsewhere).

Adds an `initialExpansion` prop to PierreFileTree so the diff modes
(small change-set) open all folders by default while browse mode
(whole repo) stays "closed".

…file viewers

Both `PierreDiffView` and `PierreFileView` repeated the same line-ref
context-menu wiring: a `SelectedLineRange` signal, a reset effect on
path change, an `onLineSelected` adapter, and a `buildItems` returning
"Copy path" plus an optional "Copy <path>:<line>". Two call sites is
below the rule-of-three threshold, but the protocol is locked in
lockstep — adding a third menu entry was a two-file edit.

Centralized in `useLineSelection(path: () => string)`. Each wrapper
shrinks to:
  const selection = useLineSelection(() => props.path);
  // ... onLineSelected: selection.handleSelect
  // ... <CodeContextMenu getItems={selection.buildItems} />

Hickey "Simple Made Easy" finding: concept multiplication. Two
implementations of one user intent; the hook collapses them to one.

Net: -43 lines, no behavior change. Tests still pass (14 scenarios,
143 steps).