frank-dragoon: lower the context to 200704 (ctx and pool together)

Frank's call the same evening as the native-payload cutover: HALOGEN_CTX and
HALOGEN_KV_POOL_POSITIONS both 262144 -> 200704 (a multiple of 4096, the rung
frank-zealot already runs). The checkpoint's native window is 262,144 and the
engine serves anything below it, so this is a RAM decision, not a capability
limit: the KV reservation drops 7.2 GiB -> ~5.4 (the 2026-10-06 pool measured
14.6), and by the FLAGS.md law -- RAM the pool takes is RAM that n-gram table
loses -- the freed positions become page cache for the 47.68 GiB table that
long prompts read. Engine-side total ~74 GiB instead of 75.8.

The 400-zone law is invariant to the value, so the harness moves WITH the
ceiling: models.yml contextWindow 217088 -> 155648 = ceiling - 45056, keeping
the gap that absorbs the chars/4 under-count (worst-case request ~156.2k vs
the 200,704 ceiling, ~44k margin). Compaction now fires at 85% = 132,300 est
(~136k measured); the 180k target of the 262,144 era is unreachable because
the window itself is 155,648. maxTokens 45056 and the coupled
cap/timeout 65536/7200 are untouched.

Cost stated plainly: with pool == ctx, ONE maximum-length request fills the
pool, so two long conversations never coexist (two of <=100k do). Acceptable
because frank-dragoon carries only the slow role and the security-reviewer
subagent, not the interactive workhorse.

Seam re-keyed: the fit-law test now proves the invariant at the new pair, and
the pool law (ctx <= pool <= slots * ctx) still holds with pool == ctx.

scripts/frank-dragoon.service

@@ -1,5 +1,5 @@
 [Unit]
-Description=halogen-flash-server container (Quat3rnion NATIVE v2 abliterated Qwen3.8-Flash-Next, MTP spec decode, 2 slots over ONE 262144-position pool, vision ON), root systemd unit (dankclaw, frank-dragoon, Strix Halo iGPU)
+Description=halogen-flash-server container (Quat3rnion NATIVE v2 abliterated Qwen3.8-Flash-Next, MTP spec decode, 2 slots over ONE 200704-position pool at ctx 200704, vision ON), root systemd unit (dankclaw, frank-dragoon, Strix Halo iGPU)
 After=network-online.target
 Wants=network-online.target