fix(madara): list coin-locked Tangerine Archive chapters with an honest locked notice

[RibatTRW]

Stacked candidate fix for lnreader#2564 (base is that PR's branch fm/lnreader-plugins-2555-tangerine, not the default branch).

Fixes the gap PR 2564 documented: premium (coin-locked) chapters were left out of the chapter list. They now appear, marked as locked, and opening one gives an honest locked notice instead of a blank chapter - so reader prev/next steps through them instead of skipping them.

What changed

plugins/multisrc/madara/template.ts (additive and flag-gated; other Madara sources take the old code path unchanged):

• New listLockedChapters option in MadaraOptions.

• parseNovel: locked rows (premium-block, href="#") are kept. Their canonical /series/<slug>/chapter-<n>/ URL is rebuilt from the row's chapter number (Chapter 175 -> chapter-175/, dots become dashes, Chapter 176 🔞 -> chapter-176-🔞 when a non-ASCII token is part of the slug), the existing 🔒 prefix is kept, and chapterNumber/order stay aligned with the full live inventory. The non-ASCII rule was checked against the real hrefs of 1036 free rows on the live site (1035 exact, the single miss being a duplicate title that has a real href and is never reconstructed).

• Locked rows' releaseTime comes from the site's own unlock countdown: "Unlocked in 4 weeks" becomes the future date it names (as YYYY-MM-DD); "TBA" claims no date. The template's parseData would have subtracted instead and reported a date in the past.

• New parseChapter helper parseLockedChapter: when the fetched page contains .reading-content .content-blocked, it returns e.g.

  🔒 This chapter is locked on Tangerine Archive.
  It costs 10 coins to unlock.
  Unlocked in 4 weeks.
  

  Price is read from the block's coin-<N> class; the countdown is read from the series chapter-list ajax (the only place the site renders it) by chapter id, with a price-only fallback if that lookup fails.

• A derived URL can land on the series page when the real slug is not chapter-<n> (peer-verified cases: emoji-suffixed titles, duplicate chapter numbers). Those rows now return an explicit "could not be loaded" notice instead of coming back empty.

plugins/multisrc/madara/sources.json + plugins/multisrc/madara/README.md: tangerinearchive opts in with listLockedChapters, the existing hasLocked setting (so users can hide locked chapters again), and versionIncrements: 1 (version 2.2.1).

Chapter name metadata in the list is deliberately unchanged beyond the existing 🔒 marker.

What was probed (anonymous, read-only; no cookies, no login, no purchase, no bypass)

• POST /series/<slug>/ajax/chapters/ is the full inventory in one response; premium rows are li.premium.coin-N.data-chapter-<id>.premium-block with href="#" and a countdown or TBA. Built the URL rule from the row's visible number and verified derived URLs against the row's data-chapter-<id> (#wp-manga-current-chap data-id on the fetched page) across 5 series.
• Premium pages answer 200 with .reading-content .content-blocked and no body; free pages have real prose (~6.4k-10.5k chars) and zero content-blocked. Countdown is absent from the chapter page, present only in the list.
• Verified free -> locked -> free walks live in both directions, e.g. 159 -> 160 -> 161 -> 162 -> 161 -> 160 (garden-of-may) and 51 -> 52 -> 53 -> 54 -> 53 -> 52 (i-thought-i-was-the-monster-dukes-fake-tranquilizer): free chapters return prose, locked ones return the notice.
• Plugin chapter counts now equal the live ajax inventory: garden-of-may 212 (160 free + 52 locked), i-thought... 173 (53 + 120), me-the-weakest... 198 (148 + 50). Before the change the plugin returned only the free counts.
• Edge cases verified live: the emoji-suffixed premium rows Chapter 175 🔞 / Chapter 176 🔞 now reconstruct to /chapter-175-%F0%9F%94%9E/ and /chapter-176-%F0%9F%94%9E/, whose pages carry the row's own data-id (16719 / 16720) and return the locked notice; Chapter 242 - 🔞 stays plain /chapter-242/ (a dash makes the emoji a title, not a slug token); a deliberately wrong path (/chapter-176/) returns the "could not be loaded" notice instead of a blank chapter; the duplicate Chapter 166 row returns a locked notice, never free prose.
• hideLocked verified both ways with a stubbed storage: off -> 212 chapters / 52 locked, on -> 160 chapters / 0 locked.

Validation

• npm run build:multisrc and npm run build:compile pass.
• npm run check:plugin -- 'plugins/english/TangerineArchive[madara].ts' passes all four steps (popularNovels 12, searchNovels pass, parseNovel 173 chapters, parseChapter 14497 chars).
• Custom plugin-level probe: 54/54 checks pass (counts, derived URLs, notices, release times, both-direction walks); edge-case probe 6/6.
• Shared-template guard: SleepyTranslations[madara] passes all four checks identically on base and head. ZetroTranslation[madara] popularNovels fails on the base commit too (dead site), and BoxNovel/NovelNice/LunarLetters/WooksTeahouse are site-level unreachable - none caused by this change.
• prettier --check and eslint on the changed file pass (repo-wide eslint has pre-existing errors in untouched files).

Not tested

• No entitled-session test. Nothing here attempts to bypass, purchase, or log in around the coin-lock: locked bodies are server-gated and the plugin only reports that they are locked. The unlock flow was not exercised with a registered account or coins, so the notice is verified as an honest locked state, not as a post-unlock read.
• Reader-app rendering of the notice (verified at plugin API level only).
• The site's own countdown rounding: the list's unlock date is derived from "Unlocked in N ..." and can differ from the exact unlock time by up to a day or two.

Related: lnreader#2564, lnreader#2555