chore(release): v0.26.0 — series-3 decode correctness

Two body-model rewrites, a systematic scale error affecting every
geophone reading the system ever produced, a recovered file format, and
two artifact-hygiene bugs where stale files outlived the decodes that
made them.

  - geo full scale is 32000 ADC counts, not 32768 (every reading 2.34% low)
  - the waveform body is a record chain, not a tag stream
  - the histogram block is big-endian, with a terminal tail
  - sub-minute intervals pack several per block (415 files recovered)
  - three more defects found by a full-corpus sweep, each masking the next
  - stale .h5 files and stale shape_* columns are now cleared, not left

All 11,603 series-3 binaries in the production snapshot pass every check.
Ground truth: 1,211/1,211 histograms exact per-interval, 75/75 waveform
sample counts exact, multi-interval fixture exact on all 45,680 values.

Also corrects a changelog note that went stale within the same day: the
"3 of 75 events still truncate" item was resolved by the record-chain
rewrite, and the remaining open items are now listed explicitly.

CLAUDE.md gains a "Where things stand" block at the top — the header had
been reading v0.21.0, four releases behind, which is the first thing you
see when picking the project back up.

Tests: 259 passed; the 16 failures are pre-existing (gitignored
fixtures) and unchanged from baseline.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog

sfm/server.py

@@ -90,7 +90,7 @@ app = FastAPI(
         "Implements the minimateplus RS-232 protocol library.\n"
         "Proxied by terra-view at /api/sfm/*."
     ),
-    version="0.25.0",
+    version="0.26.0",
 )
 
 # Allow requests from the waveform viewer opened as a local file (file://)