Add triage tests, prepare-export, and UI fixes for Levkin migration.

Cherry-pick heuristics, manifest merge, global file search, scrollbar styling, and pytest/Playwright coverage unblock review and filtered export for mmetl.

docs/HANDOFF.md

@@ -2,7 +2,8 @@
 
 **Repo:** https://git.levkin.ca/ilia/slack-sieve (public)  
 **Clone:** `git clone git@git.levkin.ca:ilia/slack-sieve.git`  
-**Last updated:** 2026-05-29
+**Vikunja:** [todo.levkin.ca → Homelab → slack-sieve](https://todo.levkin.ca) (`SLK`)  
+**Last updated:** 2026-06-03
 
 ---
 
@@ -17,7 +18,7 @@ Official Slack export (JSON)
     → make hydrate          # __uploads/ via xoxe URLs in export
     → make preset-skips     # optional noise-channel skips
     → make review           # manifest.json (gitignored)
-    → prepare-export        # TODO — filtered Slack-shaped folder/zip
+    → make prepare-export   # prepared-export/ (filtered Slack shape)
     → mmetl transform slack
     → mmctl import
 ```
@@ -46,6 +47,9 @@ make review              # http://127.0.0.1:8765
 
 make hydrate             # re-download attachments if needed
 make preset-skips        # apply presets/levkin-skips.json (safe to re-run; keeps your channel decisions)
+make cherry-pick         # bulk data/files picks on priority channels (optional)
+make prepare-export      # after review — filtered export for mmetl
+make test                # pytest + Playwright
 ```
 
 ---
@@ -119,16 +123,21 @@ Copy and edit for another workspace.
 
 ---
 
-## TODO (next implementer)
+## Open tasks (source of truth)
 
-1. **`scripts/prepare-export.py`** — read `manifest.json`, emit filtered Slack export dir/zip (`__uploads/` + selected JSON days, thread parents included).
-2. **Pilot import** — one small channel through `mmetl` → `mmctl` on Mattermost VM; verify threads, files, users.
-3. **User mapping** — optional `fetch-emails` or Slack ID → Mattermost username map for `mmetl`.
-4. **Makefile** `make prepare-export` + doc section in README.
+Tracked in **Vikunja → Homelab → slack-sieve**. Update here when scope changes.
+
+| P | Task | Owner | Status |
+|---|------|-------|--------|
+| **P1** | **Channel review in UI** — `make review`, finish 14 undecided + 3 partial ([order](#suggested-review-order)); save manifest | @you | ⏳ **next** |
+| **P1** | Pilot import: one channel via `make prepare-export` → `mmetl` → `mmctl` on MM VM `10.0.10.237` | @agent | ⏳ blocked on review |
+| **P2** | User mapping: Slack ID → Mattermost username for `mmetl` | @agent | backlog |
+| **P3** | Re-hydrate 13 files that returned HTTP 401 (expired export token) | @you | optional |
+| — | `scripts/prepare-export.py` + `make prepare-export` | @agent | ✅ done |
 
 ### Mattermost / homelab
 
-- SSO: Authentik — see ansible `docs/guides/mattermost-authentik-gitlab-oauth.md`
+- SSO: [authentik-apps.md#mattermost](https://git.levkin.ca/ilia/ansible/src/branch/master/docs/guides/authentik-apps.md#mattermost) (ansible)
 - Import docs: https://docs.mattermost.com/administration-guide/onboard/migrate-from-slack.html
 
 ---
@@ -143,6 +152,10 @@ slack-sieve/
   scripts/
     hydrate-export.sh
     preset-skips.py
+    auto-cherry-pick.py
+    prepare-export.py
+    build-test-fixture.py
+  tests/                # pytest + Playwright (mini-export fixture)
   presets/
     levkin-skips.json
   manifest.json       # gitignored — your work in progress