feat(v4.0.0): POST is the kernel's -- the boot feeds the cases, and nothing of the harness is on the node

The boot runs POST with the runner (v4/system/post.c) after the capsules:
it feeds the 538 cases to the node and judges them from outside.  A
case's printing no longer reaches the console.  What the cases define
stays in the dictionary, as in v3; the system is sealed after POST and
the boot prints PARITY:V4_SYSTEM word_count=N dict_hash=..., as v3 prints
its parity after POST.

Gone: capsules/v4/post79.4th and its blocks 7000 up; the harness words;
(CATCH) and (EMIT-HOOK), with what EMIT and the prompt loop did for them.

The generator runs v3 on the lines as the kernel sends them, without the
capsule's "T| ".  One expected result follows from that: >IN.initial
prints 6, not 9.

make -C v4 test, sanitize and hosted-check pass; amd64, aarch64 and
riscv64 boot, POST 538 of 538, word_count=411, dict_hash
0x6fb1d09418b189ee on all six: logs/20261007-105118, -105335, -105651.
T{ is unknown at the prompt; RS1 prints 42 42 before and after COLD.  A
scratch build with one expectation changed names the case and ends
PARITY:FAIL, POST: FAILED.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

v4/tools/mkpost.py

@@ -240,10 +240,14 @@ ANSI = re.compile(r"\x1b\[[0-9;]*m")
 def run_v3(v3, cases):
     """Runs the cases in one session.  Returns a list, one entry per case:
     None if v3 did not get through it, else (error, stack, output)."""
-    script = [": T| ; IMMEDIATE", ": TCLR BEGIN DEPTH WHILE DROP REPEAT ;"]
+    # The lines are run as the kernel sends them to the node: without the
+    # "T| " each began with when they were lines of a capsule.  A case that
+    # looks at where it is in its line (>IN) depends on it.
+    script = [": TCLR BEGIN DEPTH WHILE DROP REPEAT ;"]
     for n, case in enumerate(cases):
         script.append('TCLR DECIMAL FORTH DEFINITIONS ." [[B%d]]"' % n)
-        script.extend(case["lines"])
+        assert all(line.startswith("T| ") for line in case["lines"]), case
+        script.extend(line[3:] for line in case["lines"])
         script.append('." [[E%d]]" BASE @ DECIMAL .S BASE ! ." [[S%d]]"' % (n, n))
     script.append("BYE")
     done = subprocess.run([v3, "--log-none"], input=("\n".join(script) + "\n").encode("latin-1"),