wcc+w6c_ww: typed dot-read resolver — kill both silent N_DOT fallbacks (F4)

A typed depth-2+ field chain behind an index/deref spine
(threads[0].cap.end, (*p)[i].f.g) aborted the cgdot chain walker
(N_IDENT roots only) and fell into the module-qualified-leaf fallback
— a silent `MOVQ <leaf>(SB)` global read of a colliding symbol
(p6min10 exit 66) or a link error. Single-dot reads behind a deref-
index ((*ts)[i].pc, (*p)[i].slicefield) fell into the bottom catch-all
instead, which is offset- and header-blind: offset-0 scalars read
correctly by COINCIDENCE, nonzero offsets and slice headers were
silently wrong in BOTH stages (FA3, pA5). `&threads[0].cap` dropped
the address-of silently and SEGFAULTed at the deref (task #6,
reviewer-A route).

cgplaceaddr (C1) grows an N_IDENT root (local / let / DATA-backed
def) and the N_INDEX base gate relaxes to recursion, so indexed-ident
and deref-rooted spines resolve; enumerated arms still dispatch first,
keeping every pre-C1 shape's asm. case N_DOT routes any TYPED read no
arm matched through the resolver (scalar fldloadop, float X0, str/
slice 3-word header, [N]T address); the module-leaf fallback is gated
to UNTYPED chains, the catch-all to untyped-str pseudo-fields, and
the TK_AMP tail is resolver-or-loud. Leaf kinds without a register
convention (tagged, aggregate) and unaddressable shapes die LOUD
(rule 7). wwstage mirrors symmetrically; two of its arm gaps must not
take the resolver (its sequence differs from cstage's arms — cs!=ww):
ident-indexed alias reads loud-cite C3 (task #8) and non-local-rooted
ptr-chains loud-cite task #37. A third verdict divergence is comment-
documented at the wwstage aggregate gate: cstage's let-init consumes
`let c = (*ts)[i].cap` BEFORE its N_DOT tail (emitting NO copy — the
F5 bug), so that shape cs-builds/ww-louds until the F5 let-copy lands
(task #7); absent from the gate corpus.

806 identroot_dot graduates from BUILD_FAIL: the C2 ident root makes
append(h.xs, v) through *holder resolve via C1.5's place consumer
(run-verified, byte-id). p6min9/p6min10 read-halves are fixed but the
probes stay blocked on the #36 literal under-copy this commit
unmasked (struct-ident field rhs copies 8B; repro filed with the
task).

test/805: +7 rows (typed depth-2 behind ident-index incl the 777
global-collision pin, deref-index, width/float/[N]u8 matrix, FA3
slice-field + .cap-behind-spine, &-route with compound-through-
pointer, C1's reject_tail graduated to stores, neutrality pins) and
+4 reject rows pinning the new loud texts; the C1.25 raw-byte
readbacks graduate to typed depth-2 reads.

test/wcc/806_append_place.c

@@ -42,8 +42,8 @@
  *                        | — nested indirect append inside the     |
  *                        | outer's value expr; pins the per-SITE   |
  *                        | @apphdrscr slot (a shared slot clobbers)|
- *   reject_identroot_dot | h.xs via *holder param (resolver ident  | BUILD_FAIL
- *                        | root unwired — was silent corruption)   |
+ *   identroot_dot        | h.xs via *holder param — C1.5's reject, | 73
+ *                        | graduated by C2's resolver ident root   |
  *   reject_spread_src    | non-ident spread SOURCE through a deref | BUILD_FAIL
  *                        | target (the #35 designed boundary)      |
  *
@@ -372,20 +372,28 @@ static const struct row rows[] = {
 	  "};\n",
 	  33, NULL },
 
-	/* Ident-rooted dot target (h.xs through *holder): the resolver
-	 * does not wire ident roots (they belong to the enumerated arms;
-	 * none exists for append yet) — pre-fix this shape silently
-	 * corrupted the frame in cstage; now it must die LOUD. */
-	{ "reject_identroot_dot",
+	/* Ident-rooted dot target (h.xs through *holder): C1.5's loud
+	 * boundary (the resolver had no ident root then; pre-FA1 this
+	 * shape silently corrupted the frame in cstage), graduated by
+	 * C2's cgplaceaddr N_IDENT root — the *holder base derefs once
+	 * inside the N_DOT hop and the header place lands on &h.xs.
+	 * Readbacks use the .len pseudo, not len(): len() of a non-tuple
+	 * N_DOT is the pre-existing F2 enumeration gap (task #10). */
+	{ "identroot_dot",
 	  "package main;\n"
 	  "type holder = struct { tag: i64, xs: []i64 };\n"
 	  "fn addfield(h: *holder, v: i64) void = { append(h.xs, v); };\n"
 	  "export fn main() i32 = {\n"
 	  "\tlet hl: holder = holder { tag = 2, xs = [] };\n"
 	  "\taddfield(&hl, 9);\n"
-	  "\treturn 0;\n"
+	  "\taddfield(&hl, 11);\n"
+	  "\tif (hl.xs[0] != 9) { return 1; };\n"
+	  "\tif (hl.xs[1] != 11) { return 2; };\n"
+	  "\tif (hl.xs.len != 2) { return 3; };\n"
+	  "\tif (hl.tag != 2) { return 4; };\n"
+	  "\treturn 73;\n"
 	  "};\n",
-	  BUILD_FAIL, "#15: append() target place unsupported (rule-7)" },
+	  73, NULL },
 
 	/* The FA4 designed boundary (task #35, old #37): a spread SOURCE that is
 	 * not an ident local must stay loud even now that the deref