fix(xai): scope native web_search to swap-only + reconcile composer ctx to 200k

Salvage corrections on top of @XVVH's #44341:
- Make native web_search injection a 1:1 swap for an already-present client
  web_search function, NOT an additive grant. The original unconditionally
  appended {"type":"web_search"} on every is_xai_responses turn with any
  tools, force-enabling Grok server-side search even when the user never
  enabled the web toolset (bypassing Hermes web-provider config + tool-trace
  plumbing). Now gated on a client web_search actually being present.
- Reconcile grok-composer context to 200000 (merged in #47908) rather than
  262144; 200k is xAI's published usable context window for Composer 2.5,
  262144 is the /v1/responses input+output budget.
- Update tests to match scoped behavior + add a no-web-toolset guard test.
- AUTHOR_MAP entry for #44341 salvage.

Incomplete-guard (server-side *_call items at in_progress no longer flip
has_incomplete_items) and preflight built-in-tool allowlist kept as-is.

scripts/release.py

@@ -49,6 +49,7 @@ AUTHOR_MAP = {
     "zheng@omegasys.eu": "omegazheng",
     "220877172+james47kjv@users.noreply.github.com": "james47kjv",
     "yuhanglin@YuhangdeMac-mini.local": "1960697431",
+    "admin@fent.quest": "XVVH",
     "despitemeguru@gmail.com": "definitelynotguru",
     "chaslui@outlook.com": "ChasLui",
     "rio.jeong@thebytesize.ai": "rio-jeong",