feat: show who wrote the wire in the left rail

[dimslaev]

Session 2 of 4 (rails). Adds the first left-rail panel: how the feed's current window splits by origin, and how its articles were found.

Changes

• Backend: origin_counts(session, since) in catalog/facets.py. One COUNT per Origin, built with origin_condition, zeros included. Also unlabelled and found_via grouped counts.
• Route GET /api/v1/articles/origins?since=<iso>, thin adapter, 422 on a bad since.
• Models OriginCount, FoundViaCount, OriginCounts in catalog/models.py.
• Regenerated types.gen.ts, sdk.gen.ts, schemas.gen.ts.
• Frontend: components/Rails/panels/WhoWrote.tsx, registered first in LEFT. Only change to panels.tsx is the import and the one LEFT entry. RailPanelDef is untouched.
  • Range line at the top of the body follows the Published filter. PUBLISHED_DAYS and cutoffIso are now exported from ArticlesList.tsx, and ORIGIN_OPTIONS from FeedFilters.tsx.
  • Rows are sorted by count. Bars are foreground/45 on a faint track. The active From row and its label are paper. A click sets origin, and clicking the active row clears it.
  • Footer: "Of N: x from publishers' own feeds, y found on Hacker News, z via newsletters." Every non-null found_via that isn't Hacker News counts as a newsletter.
  • At 40% opacity and inert while search is active. Query key ["articles", "origins", dateRange], staleTime 5 min.
• docs/product.md: one line under the feed section.

Where I departed from the plan

• marked_for_deletion_at is not excluded. The plan says to exclude it "same as the feed", but the feed (_filters in articles.py) doesn't exclude those rows. The plan's main rule is that the numbers always match what the From filter shows, so I kept that rule and left the marked rows in.
• unlabelled counts posts only. These are posts by an unknown publisher. A repo, paper or model from an unknown publisher already counts under its own origin. With this, total = sum(origins) + unlabelled.
• Panel title is "Who wrote the wire", not "Who wrote this week". The window can be 3 days or a month, so "this week" would often be wrong. The title matches this PR's title.
• Playwright at 1440. The plan asks that [ hides and shows the left rail, with the state surviving a reload. The merged shell (feat: add collapsible side rails to the feed #72) doesn't work that way: on a wide screen the rails are always open, [ does nothing, and only a panel's folded state is saved. The test checks what the shell actually does: [ leaves the rail visible, and folding the panel survives a reload in both directions.
• "The feed shows only writers" is checked from the feed's API response, not from row text. Every returned article must be a post from an individual publisher, and the row count must match. Row text can't tell a writer from other publishers.

Verification

• Backend: Postgres via compose (pgvector image from Docker Hub, tagged as the compose image, because the ghcr pull is blocked in this sandbox), then prestart.sh and pytest. Result: 537 passed, 1 failed. The failure is test_read_endpoints_are_public[/search?q=agents]: the test downloads an embedding model and the sandbox proxy blocks it (403). It's unrelated to this change.
• New backend tests in catalog/tests/test_routes.py:
  • every origin is listed
  • a company's repo counts as repo
  • a community post counts as media
  • an unknown publisher's post counts as unlabelled and in the total
  • since bounds the counts
  • found_via grouping, including null
  • 422 on a bad since
  • the endpoint is public
• Lint and types: ruff check, ruff format, mypy, ty and biome all clean.
• Build: bun run build passes.
• Playwright: run against a live backend and mailcatcher, using the preinstalled Chromium. Pinned 1.61.1 wants a newer browser build, so I pointed it at Chromium with a temporary local config that isn't committed.
  • tests/rails.spec.ts: all 4 pass (1440, 1000, 390, Writers click).
  • Full suite: 28 passed, 1 failed. The failure is likes.spec.ts "shows Liked / My profile / Password / Danger zone tabs". It fails the same way on master, since sign-in has no passwords and the profile has no Password tab.
• I checked a screenshot of the panel at 1440 by eye against the picker design.
• Merged latest master before opening: already up to date.

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https://claude.ai/code/session_0183b3dLpUezpQ8TCgDQnysM

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