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/staging/089/01_scmp-com.txt

@@ -0,0 +1,21 @@
+Hong Kong cryptocurrency trader targeted in HK$2 million robbery, sparking citywide hunt for suspects | South China Morning Post
+
+Hong Kong cryptocurrency trader targeted in HK$2 million robbery, sparking citywide hunt for suspects
+
+Assailants sprayed unknown substance in 22-year-old victim’s eyes during attack in Kwun Tong, before grabbing bag full of cash
+
+Police say gang fled in white car which they later abandoned before running away on foot
+
+Published: 8:14pm, 15 Jun 2021Updated: 8:52pm, 15 Jun 2021
+
+A citywide police hunt is under way for a gang of thieves after a cryptocurrency trader was sprayed in his eyes with an unknown substance and robbed of HK$2 million while he was on his way to buy bitcoin in Hong Kong on Tuesday.
+
+The suspects struck in broad daylight in the car park of Legend Tower on Shing Yip Street in Kwun Tong, shortly before 4.30pm.
+
+According to police, the 22-year-old victim was targeted after he parked his car.
+
+“While he was waiting for a lift, two men approached him and sprayed an unknown liquid into his eyes before snatching his green bag containing HK$2 million,” a police spokesman said, adding the victim said the substance had left him briefly unable to see.
+
+Officers said the two robbers fled in a white car driven by a third man, the three suspects later abandoned the car at the junction of Hoi Yuen Road and Shing Yip Street, and fled on foot heading towards Wai Yip Street.
+
+Officers combed the area, but no arrests were made. The spokesman said the victim did not request hospital treatment in the incident.

merge-output/staging/089/index.json

@@ -0,0 +1,16 @@
+[
+  {
+    "case": 89,
+    "n": 1,
+    "field": "url",
+    "url": "https://www.scmp.com/news/hong-kong/law-and-crime/article/3137401/hong-kong-cryptocurrency-trader-targeted-hk2-million",
+    "host": "scmp.com",
+    "fetched_at": "2026-09-05T12:53:43+00:00",
+    "verdict": "FETCHED",
+    "method": "raw",
+    "http": 200,
+    "chars": 1563,
+    "sha256": "e3497776882b210ca8c73434faf8970992ca5db09f136d18bcd43c2e5e35dd99",
+    "final_url": null
+  }
+]