feat(wakatime): split sections into independent per-facet keys

[thisisrick25]

Splits the coupled last30 and allTime WakaTime section keys into fully independent per-facet keys so each Total / Languages / Editors block is toggleable and orderable via PLUGIN_CONFIG.

New section keys (9 total)

• last30Total - Last 30 Days total + daily average headline
• last30Languages - Last 30 Days top languages
• last30Editors - Last 30 Days top editors
• allTimeTotal - lifetime total headline
• allTimeLanguages - lifetime top languages
• allTimeEditors - lifetime top editors
• sinceToday - all-time-total one-liner (unchanged)
• insightsLanguages - last-year languages (unchanged)
• insightsEditors - last-year editors (unchanged)

Breaking change

The previous bundled last30 and allTime keys are removed (no aliases). DEFAULT_SECTIONS is now ['last30Languages'].

Implementation notes

• Added a per-run endpoint cache so keys sharing an endpoint (e.g. the three last30* keys all read /stats/last_30_days) fetch it only once.
• renderSection remains an exhaustive switch over the 9 keys (no default).
• Graceful per-section degradation preserved.

Verification

• npm run build exit 0
• npx tsc --noEmit exit 0 (strict tsconfig satisfied)