CB-WP-0019 T01/T02: AM-4b asks what a contributor acquires

The two AM-4 budgets had the SAME scope -- one package, no dev edges --
while claiming to bound different things. AM-4b now measures the
workspace with dev edges: 57 crates / 725,258 lines where it read 29 /
317,021, having been blind to 28 crates and 408,237 lines, more source
than its own target.

Target 745,000, ~2.7% of room -- the same margin ADR-0008 D3 gave AM-4a,
applied to a number that grew because the instrument was repaired, not
because anything was added. The target moved to fit the measurement.

T02: proc-macros are COUNTED here and excluded from AM-4a, on purpose.
AM-4a asks what ships and a proc-macro never ships. AM-4b asks what is
acquired, and ADR-0007 D3's acquisition rule counts what the build
fetches -- 'it does not ship' is no answer to 'we downloaded it'. When
the rules disagree, the question each budget asks decides. Measured
share 109,585 lines / 15.1% against AM-4a's 36.2%, so ADR-0008 D2's
refusal to borrow the ratio was right by more than a factor of two.

Caught by this project's own earlier work twice: the mutation
find-string went stale and --self-test reported it BUILD-FREE (the check
CB-WP-0015 added after AM-4a's rotted for two passes), then the DFD gate
caught facts.toml carrying the old numbers.

CB-EV-0001 and ADR-0004 carried live fact: tags on historical readings.
A dated record asserting a CURRENT value is a category error, so those
occurrences are marked as-measured instead of retro-edited, and ADR-0004
gains a supersession note.

make all exits 0.

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

tools/mutation-check.py

@@ -135,10 +135,15 @@ def rows():
             mutate=("tools/dep-weight.py",
                     '"shipped-runtime": 161_000,', '"shipped-runtime": 1_000,')),
 
-        Row("AM-4b", "third-party LOC, dev toolchain <= 350,000",
+        # CB-WP-0019 T01 widened this to the whole workspace with dev
+        # edges, and the literal moved with it. The stale find-string was
+        # caught build-free by `--self-test`, which is the check
+        # CB-WP-0015 added after AM-4a's mutation rotted unnoticed for two
+        # passes. Second catch, first one that cost nothing.
+        Row("AM-4b", "third-party LOC, what a contributor acquires <= 745,000",
             verify=py + ["tools/dep-weight.py"],
             mutate=("tools/dep-weight.py",
-                    '"dev-toolchain": 350_000,', '"dev-toolchain": 1_000,')),
+                    '"dev-toolchain": 745_000,', '"dev-toolchain": 1_000,')),
 
         # Deliberately RETAINED in this denominator after its withdrawal
         # from the acceptance table. Dropping it would move M-D1-MUT from