The ``/locales/{en,ko}.json`` files have no version token in their URL,
so any browser that cached them from a previous session keeps serving
the stale copy across upgrades. When a release renames or adds i18n
keys (as this PR does — ``settings.memory_dirs.*`` →
``sources.memory_dirs.*``), ``t()`` falls through to the raw-key
fallback for every affected string until the user hard-reloads.

Passing ``{cache: 'no-store'}`` to the locale fetch bypasses the HTTP
cache unconditionally. The files are ~20 KB each and only loaded once
per language per page load, so the bandwidth cost is negligible next
to the "raw keys everywhere after upgrade" failure mode.

Bumped ``/i18n.js`` cache token (v=1 → v=2) so the fix reaches users
without requiring a manual hard reload on first page visit.

Tightens the visual hierarchy of the Sources-tab Memory Dirs panel and
replaces icon-only action buttons with explicit text labels so the
intent is readable without hovering.

Layout
------
- Single-row header: title · total count ("29 dirs") · [+ Add path]
  [Reindex all]. The total is always visible so users stay oriented
  when every group is collapsed.
- Inline add-path form, opened via "+ Add path" header toggle. Replaces
  the permanent bottom row — the form now appears between header and
  groups with [Add] [Cancel] buttons and ``Esc``/``Enter`` shortcuts.
- Categorized groups use flat separators instead of boxed cards; the
  caret (▸/▾) rotates on open, summary rows have a subtle hover tint,
  and the group count sits in a small pill next to the label.
- Summary stats ("338 files · 724 chunks") right-align inside each
  group header so the scannable columns are: label | count | stats |
  action. Red for empty groups.
- Dir rows: hover-revealed action column, monospace path (left, 1fr,
  ellipsis), pill status badge, then [Index]/[Delete] text buttons.
  Default opacity 0.45 → 1 on hover so a 26-dir Claude group doesn't
  read as button noise.
- Panel has no inner padding at the root; each sub-section carries its
  own padding so the border-bottom lines extend full-width.

Actions
-------
Per-dir and per-group action buttons switch from icon glyphs to text:

- ``↻`` (per-dir reindex) → **Index**
- ``✕`` (per-dir remove) → **Delete**
- ``↻`` (group reindex) → **Reindex**
- ``↻ Reindex all`` (header) drops the leading glyph — label alone is
  clearer and the ``btn`` styling already reads as a button.

Tooltips (``title`` attrs) keep the longer descriptions for
screen readers and hover-probing. ``aria-label`` preserved on delete.

i18n
----
New keys (en/ko parity covered by ``test_i18n.py``):

- ``sources.memory_dirs.total_one``/``total_many``
- ``sources.memory_dirs.add_btn`` → "+ Add path" / "+ 경로 추가"
- ``sources.memory_dirs.add_submit`` / ``add_cancel``
- ``sources.memory_dirs.action_index`` / ``action_delete`` /
  ``action_reindex_group``
- ``sources.memory_dirs.reindex_all`` text updated (dropped ``↻``
  prefix)

Verification
------------
- ``uv run pytest packages/memtomem/tests/test_i18n.py`` — 11 passed.
- ``uv run ruff check packages/memtomem/src`` — clean.
- Browser smoke (29 dirs, 4 categories, ko locale): panel header
  compact, category collapsed states preserve stats, hover-revealed
  action labels readable, add-path toggle opens inline form with
  focus trap and ``Esc``/``Enter`` shortcuts working.

Cache-version bumped on ``/sources-memory-dirs.js`` (1 → 2).

The Sources tab is a flex column (``#tab-sources`` uses ``display:
flex; flex-direction: column`` via ``.tab-panel``), and
``.sources-layout`` asks for ``height: 100%``. With the default
``flex-shrink: 1`` and no explicit ``flex-basis`` on the Memory Dirs
panel, that sibling's 100% demand won the flex bargaining round at
desktop viewports — the panel got shrunk from its ~243px content
height down to 2px, making it effectively invisible. Opening DevTools
changed the viewport during layout recalc, which is why the panel
would flash back into view while DevTools was open and vanish again
when it was closed.

Pinning ``flex-shrink: 0`` on ``.memory-dirs-panel`` keeps it at its
content height regardless of what ``.sources-layout`` demands. The
existing ``overflow: hidden`` on the panel + rounded corners + border
visuals still apply — only the flex sizing contract changes.

Verified at 1920x1080: panel.getBoundingClientRect().height is now
243px (previously 2px); all four category groups, the header actions,
and the sources list below all render correctly.