Remove unverified special issue data, fix DBLP entity decoding

The two special_issues entries were proof-of-concept data and could not be
corroborated: no TPDS "Edge AI Systems" or open FGCS "Serverless Computing
at the Edge" call is findable, and both named real researchers as guest
editors. Removed rather than corrected — nothing verifiable exists to
replace them with. No open special issue was found at any tracked journal,
so the field stays absent until a real CFP appears.

Audited the rest of the data while there. All 39 candidate pools come from
DBLP and all 471 digested papers reconcile against them, so the paper set
is sound. Three defects surfaced:

- DBLP returns HTML-escaped text and fetch_papers never decoded it, so 136
  entities sat in the cached pools and "Theodore Y. Ts'o" reached the
  published ATC-2024 digest. Decoded at the fetch boundary and cleaned the
  existing files through the YAML parser.
- SC event_dates recorded the exhibition window (Nov 17-19) instead of the
  conference (Nov 15-20); EuroSys ran a day long (Apr 19-24 vs 19-23).
  Both verified against the official sites, which also confirm every
  SC, EuroSys and OSDI submission deadline is exact.
- TC-2025 digest carried a paraphrased title, now matching DBLP.

EuroSys only records its spring cycle; the fall cycle has no home in the
one-deadline-per-venue schema.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -204,14 +204,16 @@ journals:
   - acronym: TPDS
     # ... existing fields ...
     special_issues:
-      - title: "Edge AI Systems: Design and Optimization"
-        guest_editors: ["Wei Zhang", "Yong Cui", "Jian Wang"]
-        cfp_url: "https://..."
+      - title: "<Special issue title, verbatim from the CFP>"
+        guest_editors: ["<Editor One>", "<Editor Two>"]
+        cfp_url: "https://<link to the CFP itself, not the journal's CFP index>"
         abstract_deadline: "Aug 15, 2026"
         submission_deadline: "Sep 1, 2026"
         notification: "Jan 2027"
 ```
 
+Every field must come from a published CFP. There is no fetcher for these, so nothing validates them — an unverified entry publishes a deadline that looks authoritative and names real people as editors. Record `cfp_url` pointing at the specific call, so any reader can check the entry against its source.
+
 Special issue deadlines appear in three places:
 - **Journal page** — a "Special Issues" table below the journal metadata
 - **Calendar page** — a "Journal Special Issues" table below the conference deadlines