feat(sources): fetch linked URLs for the 252 spreadsheet-only cases

Until now only cases 357+ (plus a few older ones) had their linked URLs
fetched; the other 252 dossiers held just the text pasted into the
spreadsheet, often only the lede. This pass fetches every linked URL for
those cases so the full text is on file before link rot takes it.

- stage_all.py: new --include-sheet-cases flag that lifts the skip on
  cases holding spreadsheet articles. Resumable as before.
- staging/: raw extracts and index.json for the 252 cases.
- sourced-articles.json, case-files-manifest.json: 188 new UNTRIMMED
  blocks. 179 cases gained at least one fetched article; 73 got none
  (49 BLOCKED, 18 THIN, 9 DEAD, 4 video/social, 3 ERROR).
- sources/*.txt: rebuilt with build_cases.py --all. Sheet pastes are
  kept; fetched blocks sit beside them under the NOT YET TRIMMED banner.
  Files previously committed with CRLF are now LF.
- wayback-availability.json: Wayback snapshots exist for 73 of the 98
  failed URL slots; input for an archive-fetch pass.
- README-START-HERE.md: progress note and next step.

verify_all.py PASSES (1836 checks).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GZZENdTLzNGsbNy4DyF1yt

merge-output/sources/027_Lee.txt

@@ -78,6 +78,48 @@ Bitcoin’s plunge turns Winklevoss twins into ex-billionaires as focus turns to
 The three robbers fled on foot and were seen turning onto North Point Road heading towards Provident Garden on Java Road. Officers scouted the area, but no arrests were made.
 According to police, the victim suffered minor hand and leg injuries. He was bandaged at the scene but did not require hospital treatment.
 
+------------------------------------------------------------------------------------------------
+FETCHED ARTICLE 1  [RAW EXTRACT — NOT YET TRIMMED]
+  !! This is the whole page as extracted. It still contains site furniture,
+  !! and may contain teaser headlines for UNRELATED cases. Trim on read-through.
+  !! Do not quote from it without checking the passage belongs to this case.
+  Source     scmp.com
+  URL        https://www.scmp.com/news/hong-kong/law-crime/article/2129665/hong-kong-bitcoin-trader-lured-bogus-meeting-and-robbed
+  Field      url
+  Retrieved  2026-09-05T12:56:12+00:00 via raw HTTP retrieval, deterministic extraction (HTTP 200)
+  Language   unknown
+  Kept       paragraphs ALL 11 paragraphs, untrimmed
+  Length     1,263 chars
+  Integrity  sha256 e853e0ab2995d291e02f2329ef41c348f3678f82ec05474a3dbce99879af7bca
+  Trimmed    NOT TRIMMED. Full page extract; trim on read-through.
+  Caveat     retrieved from a live page on the date above. Unlike text copied
+             from the spreadsheet, there is no second copy to hash it against.
+------------------------------------------------------------------------------------------------
+
+ORIGINAL (unknown, verbatim as retrieved)
+
+Hong Kong bitcoin trader lured to bogus meeting and robbed of HK$1.4 million | South China Morning Post
+
+Hong Kong bitcoin trader lured to bogus meeting and robbed of HK$1.4 million
+
+Police are searching for five men, two who posed as sellers and three who attacked victim and took his bag
+
+Published: 1:30pm, 19 Jan 2018Updated: 11:05pm, 6 Feb 2018
+
+A citywide police search was under way on Friday for five men after a local bitcoin trader was lured to a bogus business meeting and robbed of HK$1.4 million (US$180,000) on a busy street in Hong Kong.
+
+The five included two suspects who posed as sellers and arranged to meet the victim to trade bitcoin for cash, according to a police source.
+
+“The other three attacked the victim and took his bag, containing cash and a mobile phone,” he said.
+
+The attack happened in North Point, on Hong Kong Island.
+
+As of just before noon on Friday, the five suspects were still on the run, according to police.
+
+Did bitcoin just burst? How the cryptocurrency slump compares to history’s biggest fads
+
+The victim is a 34-year-old Hong Kong man surnamed Lee, who was contacted via his WeChat account on Thursday morning. He was asked to go to the Starbucks outlet on Hennessy Road, Wan Chai for a business meeting at 4.30pm.
+
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 generated from attacks-export-Gart-website.json + reported_K&R  |  case 027
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