release: v2.0.0 — series multi-select TUI

[xAlcahest]

Summary

Hyperflux 2.0.0. Adds whole-series downloading: point flux at any episode page of a supported site and it opens an interactive picker listing every episode, with the ones already on disk ticked and the rest pre-selected, downloads only what's missing, and keeps each file under the same name it has on the site. Also makes extractor configs work out of the box (the bundled config installs active, --extract-scan saves into the active dir) and lets config regexes interpolate captured variables (which is what enables the episode list). Merging this triggers the v2.0.0 release: tag, build, GitHub Release with these notes, and push the packages to Cloudsmith.

Changelog (v2.0.0)

• Download a whole series: an interactive multi-select episode picker (arrow keys / j k, space to toggle, a select all, enter download, q quit) that shows on-disk status, pre-selects the missing episodes, and downloads only those; re-running grabs just the new ones. --all / --episodes 1,3-5 for non-interactive selection.
• The picker is a clean, skills-styled terminal UI (no ncurses): scrolls through long series with no cap and redraws cleanly on resize.
• Episodes keep the site's filename on disk (e.g. DrStone4_Ep_25_ITA.mp4).
• Extractor configs active out of the box: bundled config installed into a system discovery dir; flux --extract-scan writes generated configs into the active user dir; an HTML page hints to run --extract-scan instead of being saved silently.
• Config regexes can interpolate captured {var} values (slug-anchored episode lists).

Changes

• src/tui.c, src/tui.h: skills-styled multi-select TUI (windowed scroll, no cap, wrapping-aware redraw, SIGWINCH-safe, terminal restored on every exit)
• src/text.c: series dispatch (resolve episodes, on-disk status, batch download skipping existing, remote filenames, real series header), --all/--episodes
• src/extractor.c: {var} interpolation in var/list regex args
• examples/extractors/animeworld.conf: series config (slug-anchored list, epid charset fix for -/_)
• src/test_extractor.c, src/test_tui.c: tests for regex interpolation, list capture, window/row math
• VERSION, NEWS, ChangeLog: 2.0.0
• .github/workflows/ci.yml: tui + large-N series e2e