fix(madara): list Tangerine Archive coin-locked chapters behind an opt-in option

[RibatTRW]

What this is

Candidate fix for the premium (coin-locked) chapter problem in the Tangerine Archive source from
PR lnreader#2564, stacked on that PR's branch (fm/lnreader-plugins-2555-tangerine).

Tangerine Archive links coin-locked chapters as href="#", so the plugin dropped them entirely and
opening a locked chapter returned an empty body. This change lists them with the site's real
/chapter-<n>/ path and makes parseChapter report what actually happened instead of blank text.

What changed

All of it is additive and behind a new default-off source option, so no other Madara source
changes behavior:

• plugins/multisrc/madara/template.ts
  • new includeLockedChapters?: boolean in MadaraOptions;
  • parseNovel: for premium-block rows whose href is #, rebuild the real path from the
    listing's own anchor text instead of dropping the row;
  • parseChapter: when the flag is on, read the fetched page and throw a clear error for a locked
    page (coin price from the page's coin-N gate class, plus the listing's free-unlock countdown or
    TBA), for a derived URL that fell back to the series page (no chapter page), and for a derived
    URL that resolves to a different chapter (duplicate chapter numbers).
  • releaseTime: null for rebuilt rows: the listing carries only a countdown/TBA, which parseData
    would turn into a bogus past date.
• plugins/multisrc/madara/sources.json: tangerinearchive opts in
  (includeLockedChapters: true, hasLocked: true for the app's existing hide-locked switch,
  versionIncrements: 1 -> plugin 2.2.1).
• plugins/multisrc/madara/README.md: documents the new option.

The anchor-text rule (non-uniform by design)

Verified against the live listings; the rule is not a plain Chapter (\d+) match:

listing text	rebuilt path
Chapter 250 - (End of the Side Stories)	chapter-250/ (title suffix dropped)
Chapter 239 - SS-IV. (AU)	chapter-239/
Chapter 27.2	chapter-27-2/ (dot -> dash)
Chapter 176 🔞	chapter-176-%F0%9F%94%9E/ (non-ASCII token directly after the number is part of the site's slug)
Chapter 242 - 🔞	chapter-242/ (a - separator starts a title, not the slug)

The page-identity guard (the gap this PR closes beyond the sibling candidate)

Each rebuilt row's own data-chapter-<id> is carried into parseChapter and compared with the
fetched page's #wp-manga-current-chap[data-id]. villain-let-me-touch-you has two premium rows
numbered Chapter 166 (ids 16701 and 16700); /chapter-166/ serves 16700, so the notice names the
chapter the URL actually serves instead of presenting it as the row the reader picked. A derived URL
that silently renders the series page throws a "no chapter page" error instead of returning the
series summary.

What was probed (live, anonymous, read-only - no cookies, no sessions, no nonces, no purchases)

• npm run build:compile and npm run build:multisrc pass; eslint and prettier --check on the
  changed files pass.
• npm run check:plugin on the generated Tangerine plugin: PASS (popularNovels 12,
  searchNovels PASS, parseNovel 173 chapters, parseChapter 14497 chars).
• Shared-template guard: npm run check:plugin on two unrelated Madara sources with the flag off -
  SleepyTranslations[madara] PASS (16 novels / 44 chapters / 9872 chars) and
  Lovelyblossoms[madara] PASS (16 novels / 5 chapters / 15373 chars). A third,
  CitrusAurora[madara], also passes in the custom probe.
• Custom behavioral probe (.scratch/probe-plugin.mjs, 28/28 checks) against the generated plugin:
  • garden-of-may: 212 chapters listed = 160 free + 52 locked, exactly the live ajax list; every
    locked path equals the path derived independently from the live row, every free path equals the
    live href;
  • free chapter-160/ parses 6538 chars of prose; locked chapter-161/ throws
    "it costs 10 coins, it unlocks for free in 1 day"; locked chapter-212/ throws TBA; a wrong
    derived slug throws the missing-page error;
  • villain-let-me-touch-you: 191 chapters = live list; Chapter 176 🔞 rebuilds the emoji slug
    and throws the locked error; the duplicate Chapter 166 pair is listed and the read names the
    served chapter;
  • in-the-doghouse Chapter 250 - (End of the Side Stories) -> chapter-250/;
    how-to-survive-as-a-supporting-male-lead Chapter 27.2 -> chapter-27-2/;
  • 4 sampled rebuilt paths resolve to the row's own chapter page (page data-id == row id, gate
    present);
  • the three unrelated sources have includeLockedChapters undefined and take the unchanged path.
• Independent catalogue census (19 series via wp-manga-sitemap.xml, 3359 rows: 672 premium +
  2687 free): the slug rule reproduces 2686/2687 free hrefs (2669 identical + 17 equal after
  percent-decoding; the single miss is a free duplicate with a real href), and 0 premium rows lack
  a leading Chapter <n>.

What was NOT tested

• No entitled session. Locked bodies are gated server-side; nothing here logs in, unlocks, or
  spends coins, so the actual prose of a still-locked chapter was not read. The plugin reports the
  gate honestly instead of serving it. The only routes to the prose remain the site's own scheduled
  free unlock and an owner-provided entitled session.
• No purchase/buy endpoint, no nonce or session forging, no third-party copies of the gated text.
• The countdown text comes from the listing row (it is not on the chapter page); if the listing
  cannot be read in the same session, the locked error still fires from the page alone, just without
  the countdown.
• Only tangerinearchive enables the option; other Madara sources were checked for non-regression,
  not for the feature.