Trim comments across Rust and webapp source to direct one-liners (ticket 030)

Pass over src/*.rs, webapp/src/**, and the in-app "?" docs prose:
condensed multi-paragraph doc comments to single lines that state the
non-obvious why, deleted comments that only restated adjacent code, and
tightened the Docs.tsx help-panel wording. No logic, structure, or code
formatting changed — verified via cargo test (143 passed) and
tsc -b && vite build.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

webapp/src/components/PanelChart.tsx

@@ -15,24 +15,17 @@ import {
 } from 'recharts'
 import type { ChartType, PromqlSeries } from '../lib/api'
 
-/// Renders a label combination as a short, stable string for use as a series
-/// key/legend entry — e.g. `{"path":"/a"}` -> `path=/a`. A series with no
-/// labels at all (a bare metric name with no matchers) renders as `value`.
+/// Renders a label combination as a series key/legend string, e.g. `{"path":"/a"}` -> `path=/a`; no labels renders as `value`.
 export function seriesLabel(labels: Record<string, string>): string {
   const entries = Object.entries(labels)
   if (entries.length === 0) return 'value'
   return entries.map(([k, v]) => `${k}=${v}`).join(', ')
 }
 
-// Fixed, small categorical palette (rather than pulling in a colour-scale
-// dependency) — cycles if there are more series than colours.
+// Fixed, small categorical palette to avoid a colour-scale dependency; cycles if there are more series than colours.
 const COLORS = ['#38bdf8', '#f472b6', '#a78bfa', '#4ade80', '#fbbf24', '#fb7185', '#2dd4bf', '#f97316']
 
-/// A line chart with time on the x-axis, value on the y-axis, and one line
-/// per label combination (series). Points across series are merged into one
-/// row-per-timestamp dataset (recharts wants a single array of objects keyed
-/// by series name) — timestamps that only one series has are left `undefined`
-/// for the others, which recharts simply skips when drawing that line.
+// Merges series into one row-per-timestamp dataset (recharts wants a single array keyed by series name); a timestamp missing from a series is left undefined there, which recharts skips when drawing that line.
 function toLineData(series: PromqlSeries[]): { rows: Record<string, number | string>[]; keys: string[] } {
   const keys = series.map((s) => seriesLabel(s.labels))
   const byTimestamp = new Map<number, Record<string, number | string>>()
@@ -58,14 +51,7 @@ function formatTimestamp(ts: number): string {
   return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit', second: '2-digit' })
 }
 
-/// Bar/pie charts need a single scalar per series, but the input is a time
-/// series — inherently lossy. Aggregation choices (documented here rather
-/// than hidden in the code):
-///   - bar: the *latest* point per series (a snapshot of "where things are
-///     now" — the common Grafana single-stat-per-series bar use case).
-///   - pie: the *sum* of all points per series, shown as a share of the total
-///     across all series (proportion of total volume, the common Grafana pie
-///     use case — e.g. "which path got the most requests over this range").
+// Bar/pie need a single scalar per series from a time series: bar uses the latest point (current snapshot), pie uses the sum (share of total volume).
 function latestValue(series: PromqlSeries): number {
   if (series.points.length === 0) return 0
   return series.points[series.points.length - 1][1]
@@ -133,7 +119,6 @@ export function PanelChart({ series, chartType }: { series: PromqlSeries[]; char
     )
   }
 
-  // Pie: share of total across label combinations (see aggregation note above).
   const rows = series.map((s) => ({ name: seriesLabel(s.labels), value: sumValue(s) }))
   const total = rows.reduce((sum, r) => sum + r.value, 0)
   if (total === 0) {