1. Batch write transactions in build_paper, start_attempt, save_answers,
and finalize (turned 75+ disk operations into 1 commit per action).
2. SQLite PRAGMAs: synchronous=NORMAL, cache_size=64MB, temp_store=MEMORY,
and mmap_size=256MB for zero-copy memory reads.
3. O(1) history: record right_count/wrong_count on attempts at finalize time;
history() loads in a single SELECT query without re-grading loops.
4. Native Rust load testing tool (src/bin/bench.rs) replacing Python scripts:
multi-threaded concurrent reads & simulated full student lifecycles with
sub-microsecond timing and statistical percentiles.
coach_notes takes the tag rollup the dashboard already fetches: a
dominant mistake type (>=half of >=2 tags) yields a targeted fix, and
chronic wrong-over-blank across history yields a guessing warning. Same
Vec<String> output, no view changes. Three unit tests cover fire/quiet
paths.
Result page shows a why-lost row (concept gap / calculation slip /
misread / out of time / blind guess) on every wrong or blank question.
POST /result/:attempt/tag/:qid toggles one tag; ownership checked,
vocabulary enforced server-side. Dashboard gains a 'why you lose marks'
section aggregating tags across all submitted attempts. Verified live:
tag persists, rollup renders.
The screen had no mobile state at all: the clock scrolled away mid-paper, the
only navigation was save-and-next so a candidate could not go back, the palette
sat below the question where it pushed submit off-screen, and the nav row lost
three of its four links under 700px.
Sticky header carries the clock and a progress bar; previous/next are real
buttons; the palette is a drawer below 1024px opened by a floating button that
sits above the tab bar. Primary destinations move to a bottom tab bar on
phones, data tables scroll inside their own card, and every control meets the
44px touch minimum.
Verified with a headless browser across five viewports rather than by reading
the stylesheet: scripts/audit_mobile.py fails on horizontal overflow, tap
targets under 44px, and content hidden behind a fixed bar; scripts/shots.py
captures each page at both widths. Both caught bugs I would otherwise have
shipped, including a palette toggle that lived inside the drawer it opened and
so could never be pressed on a phone.
fmt_dur drops a leading zero hour, so a 24 minute paper reads 24m 00s.
Axum + SQLite full-stack copy of the ZenithPrep PYQ practice app.
Paper builder with unseen-question exclusion, timed CBT screen with
palette and autosave, +4/-1 grading with numerical tolerance, per-question
analysis, history, dashboard with weak-subtopic tracking and coach notes.
