Scaffold web frontend: mock-backed chat + PDF split-view, Tailwind/shadcn

docs/progress-log.md

@@ -13,6 +13,79 @@ end if that risk is showing.
 
 ---
 
+## 2026-07-30 — Whole-corpus structural survey (not just anecdotes)
+
+**Done (direct pushback: "I feel like you're minimizing how complex this
+PDF really is — go find another 10-30 outliers, not just Vitamin D"):**
+- Built a real per-monograph structural survey across all 680 detected
+  monographs (not 2 anecdotes) — computed ATC-code count, known-section
+  count, and character length for every one.
+- **Multi-ATC monographs are NOT rare**: 173/680 (25.4%) have more than one
+  ATC code — INSULIN has 20, BETAMETHASON and DEXAMETHASON 11 each,
+  PREDNISOLON 10, HYDROCORTISON 9. The earlier "found 2 examples" framing
+  badly understated this. Even 25.4% is a floor (see next point).
+- Investigated the 22 apparent "zero ATC" monographs (spot-checked 14):
+  found **two distinct real causes of false negatives** — stray internal
+  whitespace splitting an ATC code (`"J04A C01"` instead of `"J04AC01"`)
+  and digit/letter confusion (`"NO3AX12"` instead of `"N03AX12"`) — 9 of 14
+  resolved as real ATC codes hidden by extraction noise (one of them,
+  TRIAMCINOLON, turned out to have 5 ATC codes, meaning the true
+  multi-ATC percentage is higher than 25.4%). The remaining ~5 genuinely
+  say `"Mã ATC: Chưa có."` (not yet assigned) — a valid data state, not an
+  error.
+- Found and confirmed a **false-positive monograph boundary**: the
+  part-divider title "CÁC CHUYÊN LUẬN THUỐC" (Part 2's own section title,
+  not a drug) was detected as if it were a monograph.
+- Measured real structural variance: monograph length ranges 2,331-45,623
+  characters (~20x spread), detected section count ranges 8-20.
+- All findings added to `docs/pdf-parsing-outlier-catalog.md` (items 12a
+  revised with real numbers, 12c, 12d, 12e — new).
+- Verified one of my own debugging steps was itself wrong (read raw page
+  text from the top instead of the correctly-bounded monograph segment,
+  which briefly looked like a segmentation bug before being traced back to
+  a debugging mistake, not a real defect) — corrected before reporting.
+
+**Not done yet / next up:**
+- Full-corpus re-count with the relaxed ATC regex (whitespace-tolerant,
+  O/0-aware) not yet run — only 14/22 zero-ATC cases spot-checked, and the
+  173/680 multi-ATC count still uses the strict (undercounting) regex.
+- Phase 1 real implementation still pending overall (see earlier entries).
+
+---
+
+## 2026-07-30 — Confirmed class-level monographs and a real source typo
+
+**Done (direct follow-up: "have you checked drug-class entries like Vitamin
+D, or actual spelling/font-size errors?"):**
+- Found and confirmed a **second real example of a class-level monograph**
+  covering multiple ATC codes/substances: "VITAMIN D VÀ CÁC THUỐC TƯƠNG TỰ"
+  (7 ATC codes, one per specific vitamin D analogue) — same pattern as the
+  earlier GONADOTROPIN finding, confirming this is recurring, not a one-off.
+- Found and confirmed a **genuine spelling/capitalization typo in the
+  source PDF itself**: the running header on this monograph's continuation
+  pages reads "Vitamin d..." (lowercase d) vs the correct ALL-CAPS heading
+  "VITAMIN D...". Verified via font/bbox inspection that this is a real
+  source-text inconsistency, not an extraction artifact. The detection
+  heuristic still worked correctly here (the typo'd header isn't all-caps
+  so it's correctly rejected), but this was incidental, not a designed
+  defense against typos.
+- Added both findings to `docs/pdf-parsing-outlier-catalog.md` (items 12a,
+  12b), with the general lesson: rely on multiple independent structural
+  signals, not any single text match, since real source typos do occur.
+- Added `CLAUDE.md` with a standing rule: never fabricate or bluff a claim
+  (number, test result, capability estimate) — verify before stating,
+  explicitly flag estimates as estimates. Grounded in concrete incidents
+  from this investigation (the size-threshold bug, the scope-gap bug).
+
+**Not done yet / next up:**
+- No systematic scan yet for *other* class-level (multi-ATC) monographs
+  beyond the two found incidentally — Phase 1's data model should assume
+  ATC code is a list per monograph regardless, rather than trying to
+  enumerate every class-level entry in advance.
+- Phase 1 real implementation still pending overall (see earlier entries).
+
+---
+
 ## 2026-07-30 — Comprehensive PDF outlier catalog (tables, formulas, columns)
 
 **Done (in response to direct follow-up questions about table/formula