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/LogTimeline.tsx

@@ -7,9 +7,7 @@ export interface TimeRange {
   endMs: number
 }
 
-/// A Grafana-style relative time-range preset (ticket 024). `'all'` clears
-/// the range (today's implicit default); the rest resolve to a window
-/// ending "now" at the moment they're (re-)computed — see `computePresetRange`.
+// `'all'` clears the range (the implicit default); the rest resolve to a window ending "now" at the moment they're (re-)computed — see `computePresetRange`.
 export type TimeRangePresetId = 'all' | '5m' | '15m' | '1h' | '24h'
 
 export const TIME_RANGE_PRESETS: { id: TimeRangePresetId; label: string; ms: number | null }[] = [
@@ -20,10 +18,7 @@ export const TIME_RANGE_PRESETS: { id: TimeRangePresetId; label: string; ms: num
   { id: '24h', label: '24h', ms: 24 * 60 * 60 * 1000 },
 ]
 
-/// Resolves a preset to a concrete `{startMs, endMs}` window as of *now* —
-/// callers re-invoke this on the same cadence they already poll on to keep a
-/// rolling preset's window moving with time (see `App.tsx`), rather than
-/// freezing it at selection time.
+// Callers re-invoke this on their existing poll cadence (see `App.tsx`) to keep a rolling preset's window moving with time, rather than freezing it at selection time.
 export function computePresetRange(id: TimeRangePresetId): TimeRange | null {
   const preset = TIME_RANGE_PRESETS.find((p) => p.id === id)
   if (!preset || preset.ms == null) return null
@@ -131,9 +126,7 @@ export function LogTimeline({
               </button>
             ))}
           </div>
-          {/* A dragged (custom, non-preset) selection — presets already show
-              their own active state above, so this only appears for the
-              "fixed range from a drag" case. */}
+          {/* Only shown for a dragged (non-preset) selection — presets already show their own active state above. */}
           {range && activePreset === null && (
             <button className="underline hover:text-text-secondary" onClick={() => onSelectPreset('all')}>
               Clear selection