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/063/01_bbc-com.txt

@@ -0,0 +1,37 @@
+Men jailed for armed robbery using cryptocurrency exchange
+
+Two armed robbers who forced their victims to open cryptocurrency accounts at gunpoint in a bid to covertly steal money have been jailed.
+
+Jordan Barrett, 23, and Ted Richards, 24, used a crypto-exchange website to try and hide their tracks and cheat justice.
+
+They targeted the house in Moorhouse Road, Carlisle, in February 2020.
+
+At Carlisle Crown Court, both men admitted two counts of robbery and two counts of false imprisonment.
+
+Barrett and Richards targeted the property because Barrett believed a third man living there had been the driver in a collision which seriously injured his girlfriend, the court heard.
+
+Armed with a starter pistol and a knife, the masked duo "took the victims' phones, forced them to unlock them and then log into their online bank accounts in order to move money between the accounts," prosecutor Hannah Forsyth said.
+
+After cash was transferred, Barrett and Richards then tried to deposit £3,500 from one account to a cryptocurrency exchange website.
+
+They forced their victims to hold up ID while photos were taken and attempts were made to open bogus accounts in their names.
+
+"While the male with the knife took the pictures and forced the victims to move money between accounts, the man with the pistol stood over the others and pointed the gun - which had a torch and laser on it - at them," Ms Forsyth said.
+
+When a friend arrived at the property, one victim was urged to make him leave and warned: "Don't do anything stupid and you won't get hurt", the court was told.
+
+Barrett and Richards stole a games console and iPhone before Barrett fired the imitation firearm outside the property "as a warning".
+
+Police were alerted before the fake cryptocurrency accounts could be authenticated. Detectives and financial investigators carried out an inquiry and found the gun at Barrett's address. DNA found on the magazine and trigger belonged to Richards.
+
+Judge Nicholas Barker jailed Barrett, of Red Bank Square, Carlisle, for six years nine months and Richards, of Empire Square, Southwark, London, for six years.
+
+The judge said their victims were subjected to a "terrifying ordeal" as they believed the gun was genuine.
+
+One victim said he had since suffered from depression and anxiety, while the other man suffered nightmares and anxiety, and felt vulnerable in his own home.
+
+Following sentencing, Det Supt Jenny Beattie, of Cumbria Police, said: "The determination shown by the investigation team has been unwavering in carrying out the inquires which has led to a successful conviction.
+
+"The team's efforts are particularly impressive given the circumstances of how the criminals forced the victims to create cryptocurrency accounts, so they could attempt to evade identification, is believed to be a first to be put before a court in this country."
+
+Follow BBC North East & Cumbria on Twitter, Facebook and Instagram. Send your story ideas to northeastandcumbria@bbc.co.uk.

merge-output/staging/063/index.json

@@ -0,0 +1,16 @@
+[
+  {
+    "case": 63,
+    "n": 1,
+    "field": "url",
+    "url": "https://www.bbc.com/news/uk-england-cumbria-62879543",
+    "host": "bbc.com",
+    "fetched_at": "2026-09-05T12:54:33+00:00",
+    "verdict": "FETCHED",
+    "method": "raw",
+    "http": 200,
+    "chars": 2986,
+    "sha256": "19fba304d4b6c3b38d88703db292bf6a82c7bc949d859d98d0d8ea984931c787",
+    "final_url": null
+  }
+]