v0.3.0 — datasets engine, finance advisory, hybrid pre-retrieval

Added

• Dataset engine — a domain-neutral datasets/ capability: tabular data
  files the assistant queries through an opt-in query_dataset tool, kept
  separate from the curated wiki so numbers come from the data, never the model.
• Argentine finance advisory (finance_argentina) — a deterministic
  estimar_alternativas tool that ranks investment alternatives for a given
  amount and horizon with code-computed gains (never LLM-estimated), flags
  non-estimable instruments (equities), and carries a nominal-vs-real inflation
  disclaimer.
• finanzas-argentinas demo — a pre-ingested Spanish finance wiki with
  datasets/, a tuned wiki_config.toml, a demo guide, and its own live
  acceptance UAT (scripts/uat_finanzas.py).
• Ingest-time vocabulary subsystem — the assistant generates data/concept
  aliases while ingesting; a vocabulary linter + auto-repair keeps the alias map
  honest (collisions dropped, stale/covered/ambiguous surfaced); a coverage
  roster decides what the wiki actually covers; and a thin-page detector
  flags source chunks the wiki leaves uncovered.
• Hybrid pre-retrieval (opt-in per wiki) — code retrieves and injects wiki
  context before the model answers, gated on the coverage roster so an
  off-topic or uncovered question is refused deterministically instead of leaking
  from a tangential chunk; tiered curated-then-raw sources with answer-vs-source
  verification; and a live toggle in the read app.
• Pluggable citation/grounding guardrail and an opt-in JSONL chat trace
  (one row per turn) for offline diagnosis.
• A tabbed read app ships alongside the grid one (marimo/read_app_tabs.py).
  It is not the default and not yet documented: quickstart.py, both READMEs
  and the programmer manual still launch marimo/read_app.py, and the E2E suite
  still covers that one. Both carry the same chat, including the pre-retrieval
  toggle, so any change to the chat currently has to be made twice. Promotion —
  and the removal of the grid app — waits on a parity test proving nothing was
  lost in the move.
• Two walkthrough documents, generated from real runs. The ingestion
  walkthrough follows one small corpus through
  its whole lifecycle — first document, second, a no-op re-ingest, an edited
  source, a deletion — and the query walkthrough
  follows a spectrum of questions through both chat modes. Each is split so a
  reader with an ordinary wiki can stop half way, and each is paired with a
  capture script (scripts/capture_*_walkthrough.py) that regenerates its
  appendix, so the figures they quote come from running the pipeline rather
  than from memory.

Changed

• The ingest end-to-end test was rewritten for the current app
  (tests/e2e/test_ingest_app_v2.py, replacing test_ingest_app.py): it drives
  the wiki picker, ingest form, Activity Log, vocabulary lint lines, scan
  idempotency and cross-links through the real Marimo UI. The slower cases stay
  opt-in behind E2E_FULL=1 and E2E_DESTRUCTIVE=1.

Fixed

• Chunk breadcrumbs named the wrong section. header_breadcrumb — the
  heading path a search hit is traced back to, and what a citation names beyond
  a page number — was serialised when a chunk was closed, from the heading stack
  as it then stood. Because a heading is pushed before the size check, a chunk
  flushed at a heading boundary was labelled with the section that starts after
  it: in the shipped demo one chunk was named "Principales riesgos
  estructurales" while containing nothing of it but the heading line, and that
  section's actual text sat in the next chunk under a different name. A
  breadcrumb naming the wrong section is worse than none — it aims a citation at
  a passage the fragment does not contain.

  Two further cases came out of the same work: a chunk that merely ends on a
  heading no longer takes that section's name, and the heading outline now
  carries across page breaks, so a section running past the bottom of a PDF page
  keeps its name (and its document title) instead of restarting. The column had
  no tests; it has seven now.

• Pre-retrieval now actually retrieves. The FTS query reached SQLite FTS5 raw,
  so any natural question crashed the search and silently returned no hits — the
  gate then refused valid, covered questions. Queries are now sanitized; both
  tiers are gated on the coverage roster; a data/advisory question routes to the
  tools before any raw-doc fallback; and a generic advisory question (an amount +
  horizon, no named instrument) reaches the advisory tool instead of being
  refused.

• Citation detection recognizes the real format. A Referencia:/Fuente:
  line (what the prompt asks for and the app emits) and a source-document
  citation (.docx/.pdf) now count as grounded/cited in the chat trace and the
  eval graders, not only an inline (wiki/….md).

• Lint & repair labels advisory-only vocabulary findings clearly instead of
  reporting them as "Unknown check type".

What's Changed

• feat: dataset engine + Argentine finance advisory + finanzas-argentinas demo by @Clod in #12

Full Changelog: v0.2.3...v0.3.0