feat(frank-dragoon): raise HALOGEN_CTX to the native 262144 ceiling

The 200,704 ceiling squeezed the harness contextWindow down to 155,648
(the 400-zone fit law needs ~45k of gap under the ceiling), which is why
long dragoon sessions kept hitting the 400 zone: the harness clamps
max_tokens to window - est - 4096, its chars/4 est under-counts ~3 %,
and config.yml compacts at 95 % while the pair was designed for 85 %.

Ceiling -> checkpoint's native 262,144 (no RAM move: the KV pool stays
401,408 and is what the ledger bills; the band ctx <= pool <= slots*ctx
still holds). The harness window becomes 200,000 with a 62,144 gap.

The fit-law seam now reads the declared window from the vault page (the
one owner) and checks the arithmetic at the live 95 % trigger, so a
ceiling/window pair that drifts back together fails tests/run.sh
instead of a live session.

tests/frank_dragoon_unit.bats

@@ -3,7 +3,7 @@
 # of the abliterated Qwen3.8-Flash-Next (a .hgn flash-server payload) on the
 # Strix Halo iGPU through the halogen-flash-server CONTAINER (0.16.2,
 # digest-pinned), driven by the root unit's serve script — 2 slots over ONE
-# 200,704-position KV pool with the MTP head always on (HALOGEN_SPEC_ADAPT=0)
+# 401,408-position KV pool at the native 262,144 ceiling, MTP head always on (HALOGEN_SPEC_ADAPT=0)
 # and the vision tower mounted. 2026-10-17 cutover from the Swift1.5-finetune
 # shape, which itself cut over the halogen 27B-dense shape on 2026-10-06.
 #
@@ -85,7 +85,7 @@ good_env() {
         "FRANK_DRAGOON_VISION_BYTES=0"
         "FRANK_DRAGOON_TOKENIZER_FILES=tok.json"
         "HALOGEN_MODEL_ID=frank-dragoon"
-        "HALOGEN_CTX=200704"
+        "HALOGEN_CTX=262144"
         "HALOGEN_KV_POOL_POSITIONS=401408"
         "HALOGEN_KV_SLOTS=2"
         "HALOGEN_SPEC_ADAPT=0"
@@ -159,9 +159,11 @@ good_env() {
     reserve="$(sed -nE 's/^HALOGEN_HOST_RESERVE_GIB=([0-9]+)$/\1/p' "$ENV_FILE")"
     # The pool is ONE budget behind the slots (boot ledger form: "2 slots over
     # ONE <pool>-position KV pool, each request up to HALOGEN_CTX"), NOT
-    # a per-slot private pool. Since 2026-10-18 it is sized pool = slots * ctx
-    # (401,408 = 2 x 200,704), so two MAXIMUM-length conversations can be
-    # resident at once — frank-zealot parity on total in-flight context. What
+    # a per-slot private pool. Since 2026-10-21 the ceiling is the checkpoint's
+    # native 262,144 while the pool stays 401,408 (raised 2026-10-18): two
+    # MAXIMUM harness-length (200,000-token) conversations are resident at once;
+    # two literal ceiling-length requests would queue — widening that is a pool
+    # raise, not a window move.
     # still binds: the pool must back ONE full-length request (below that the
     # advertised per-request ceiling would be unreachable, hence pool >= ctx),
     # it must not pretend to be more than slots x ctx (pool <= slots * ctx), and
@@ -287,7 +289,7 @@ $(cat "$TEST_TMP/serve.log")"
     [[ "$output" == *"--name frank-dragoon-halogen"* ]]
     [[ "$output" == *"--publish 7770:8731"* ]]
     [[ "$output" == *"-e HALOGEN_MODEL_ID=frank-dragoon"* ]]
-    [[ "$output" == *"-e HALOGEN_CTX=200704"* ]]
+    [[ "$output" == *"-e HALOGEN_CTX=262144"* ]]
     [[ "$output" == *"-e HALOGEN_KV_POOL_POSITIONS=401408"* ]]
     [[ "$output" == *"-e HALOGEN_KV_SLOTS=2"* ]]
     [[ "$output" == *"-e HALOGEN_SPEC_ADAPT=0"* ]]
@@ -306,27 +308,32 @@ $(cat "$TEST_TMP/serve.log")"
 
 @test "the shipped env keeps the harness fit law inside the ceiling" {
     # HALOGEN_CTX is the hard per-request ceiling (a longer prompt is a 400
-    # naming the limit, never a silent truncation). The law is INVARIANT to
-    # the value: the harness window must sit ~45k UNDER it, because the
-    # harness clamps max_tokens = min(45056, window − est − 4096), compacts
-    # at 85 % of its declared window, and its chars/4 est UNDER-counts the
-    # rendered prompt by ~3 % on code/agent traffic (measured 4,450 tokens at
-    # est 152,938 on 2026-10-07 — with window == ceiling, every request over
-    # ~65 % of the window was a guaranteed 400 before compaction could fire).
-    # The shipped pair is ctx 200704 / window 155648 (lowered from
-    # 262144/217088 on 2026-10-17); the gap must absorb the error at BOTH
-    # monotone maxima of est + budget (est ≤ window − 4096):
-    #   full budget at the compaction threshold: 1.03*132300 + 45056
-    #   clamped budget at the clamp's zero point: 1.03*151552 + 0
-    # and the compaction request that rides on frank-zealot (its
-    # 200,704-token slot) must fit: input ≈ threshold − keepRecent(20k).
-    grep -qE '^HALOGEN_CTX=200704$' "$ENV_FILE"
-    ctx=200704
-    hw=155648; mt=45056
-    thr=$(( hw * 85 / 100 ))
+    # naming the limit, never a silent truncation). The law: the harness
+    # window must sit ~45k UNDER the ceiling, because the harness clamps
+    # max_tokens = min(45056, window − est − 4096), compacts at the trigger
+    # percent of its declared window, and its chars/4 est UNDER-counts the
+    # rendered prompt by ~3 % on code/agent traffic (measured 4,450 tokens
+    # at est 152,938 on 2026-10-07 — with window ≈ ceiling, every long
+    # request is a guaranteed 400 before compaction can fire). The 2026-10-21
+    # pair: ceiling 262144 (native) under a harness window of 200,000.
+    # The declared window is read from the endpoint page — the one owner —
+    # so env, models.yml and page that disagree FAIL HERE, not as a 400
+    # mid-session (the recurring failure this seam exists for).
+    grep -qE '^HALOGEN_CTX=262144$' "$ENV_FILE"
+    ctx="$(sed -nE 's/^HALOGEN_CTX=([0-9]+)$/\1/p' "$ENV_FILE")"
+    page="$ROOT/serverAppConfigs-docs/LLM/frank-dragoon.md"
+    grep -qE 'contextWindow: 200000' "$page"
+    hw="$(grep -oE 'contextWindow: [0-9]+' "$page" | head -1 | grep -oE '[0-9]+')"
+    mt=45056
+    # Invariant checked at the live 95 % trigger (config.yml
+    # thresholdPercent) — strictly stronger than the 85 % design point.
+    # Both monotone maxima of est + budget (est ≤ window − 4096):
+    thr=$(( hw * 95 / 100 ))
     [ $(( thr * 103 / 100 + mt )) -le "$ctx" ]
     zero=$(( hw - 4096 ))
     [ $(( zero * 103 / 100 )) -le "$ctx" ]
+    # The compaction request rides on frank-zealot's 200,704-token slot:
+    # input ≈ threshold − keepRecent(20k).
     [ $(( (thr - 20000) * 103 / 100 )) -le 200704 ]
 }