release(v5.10.1): drop gemini-bridge from the pipeline; correct the T1 §6 PoC status

gemini-bridge is dropped by operator directive (three repetitions). The drop is
permanent, not a wait-for-SDK-upgrade state, so the change clears every LIVE
surface that could still steer a run toward the agent and leaves the historical
record alone.

Live surfaces cleared: agents/gemini-bridge.md deleted; trekresearch (bridge
launch block, --local help, high-effort always-on pair, stats record,
degradation list), trekplan, trekbrief, research-orchestrator (mode table,
agent table, prompting block, summary line), README (feature prose, mode table,
agent prose, mermaid EXTERNAL node, conditional legend, optional-MCP
requirement, --local section), CLAUDE.md, settings.json (the whole
trekresearch.geminiBridge block), both templates, architecture.md,
command-modes.md.

trekplan high-effort Adversarial Pass 2 now degrades EXPLICITLY: it emits its
section with status "unavailable, skipped" instead of failing or vanishing. A
high-effort plan carrying no Pass 2 marker is indistinguishable from one whose
Pass 2 crashed, which is the failure mode this wording exists to prevent.

gemini_used is deliberately KEPT as a vestigial trekresearch stats field pinned
to false. Removing it would break the observability export schema for existing
consumers, and the directive was about the agent, not the field.

Not touched: CHANGELOG history and the measurement/decision docs keep their
gemini references. They record what a past version did or what was measured
then; rewriting them is the same defect class as bumping a version string
inside a measurement doc.

Driven test-first. Five new pins in tests/lib/doc-consistency.test.mjs, verified
RED before the edits, including a KNOWN-POSITIVE CONTROL asserting the
historical records still DO carry gemini references — so the empty result on
live surfaces is a measurement and not a broken query (Verifiseringsloven
ansikt 4). Agent inventory 24 -> 23 (20 spawnable + 3 orchestrator reference
docs); the <example>-block floor moves 34 -> 32 because an agent legitimately
left the inventory, not because examples went missing from a surviving one.

Docs: docs/T1-cc26-delegated-orchestration.md §8 item 3 claimed both the §6
synthesis-agent PoC and the §5 bake-off were "designed but unbuilt". That was
written in S7 and falsified the same afternoon by S12, which ran the §6 PoC and
recorded Δ main-context (faithful flow) = 0.0%, NEGATIVE. The stale wording is
what caused the settled PoC to be re-ordered as new work on 2026-09-02, so it is
struck rather than deleted and §6 gained a RUN AND DECLINED status block. The
finding is structural, not stochastic: Phase 5 spawns the exploration swarm
foreground (trekplan.md:158,338-341), so the outputs are already resident in
main before Phase 7 — delegating only the Phase-7 digest evicts nothing.

Also measured 2026-09-03 (CC 2.1.259): claude -p --output-format stream-json
runs on subscription auth with no ANTHROPIC_API_KEY and now emits a
subagent_stats block, so S12's environment-block premise is half stale. Recorded
in §8 item 4. It lowers the cost of §5; it changes nothing about §6.

Suite 1041 (1039/0/2), up from 1036 by exactly the five tests added.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

commands/trekresearch.md

@@ -32,7 +32,7 @@ Supported flags:
 1. `--quick` — lightweight research, no agent swarm. The command itself does
    3-5 targeted searches inline. Set **mode = quick**.
 
-2. `--local` — only codebase research. Skip external agents and gemini bridge.
+2. `--local` — only codebase research. Skip external research agents.
    Set **scope = local**.
 
 3. `--external` — only external research. Skip codebase analysis agents.
@@ -121,7 +121,7 @@ Usage: /trekresearch <research question>
 Modes:
   default       Interview → foreground research (local + external) → brief
   --quick       Interview (short) → inline research (no agent swarm)
-  --local       Only codebase analysis agents (skip external + Gemini)
+  --local       Only codebase analysis agents (skip external research)
   --external    Only external research agents (skip codebase analysis)
   --fg          No-op alias (foreground is the only mode as of v2.4.0)
   --project     Write brief into an trekbrief project folder (auto-indexed)
@@ -240,8 +240,8 @@ Then continue to the next phase inline.
 > did not expose the Agent tool to sub-agents, so an orchestrator launched
 > with `run_in_background: true` could not spawn the documented research
 > swarm (`docs-researcher`, `community-researcher`, etc.) and silently
-> degraded to single-context reasoning without WebSearch / Tavily / WebFetch
-> / Gemini. As of CC 2.1.172 sub-agents can spawn sub-agents (up to 5 levels
+> degraded to single-context reasoning without WebSearch / Tavily / WebFetch.
+> As of CC 2.1.172 sub-agents can spawn sub-agents (up to 5 levels
 > deep), so that block no longer holds — a delegated redesign is under
 > evaluation (see `docs/cc-upgrade-2.1.181-decision-matrix.md`, W1/CC-26).
 > Until then, running the phases inline in main context keeps the swarm
@@ -391,11 +391,6 @@ Launch the new research-specialized agents:
 For each external agent, pass: the research question, specific dimensions to
 investigate, and any context from the interview.
 
-### Bridge agent (scope = both or external, if enabled)
-
-Launch `gemini-bridge` with the research question. Do NOT include findings from
-other agents — the value of Gemini is independence.
-
 ### Launch rules
 
 - Launch ALL selected agents **in parallel** in a single message
@@ -756,7 +751,7 @@ Present a summary to the user:
 **Engine (effective):** {swarm | deep-research}{, with fallback reason if it fell back}
 **Confidence:** {overall confidence 0.0-1.0}
 **Dimensions:** {N} researched
-**Agents:** {N} local + {N} external + {gemini: used | unavailable | skipped}
+**Agents:** {N} local + {N} external
 
 ### Key Findings
 - {Finding 1}
@@ -801,7 +796,7 @@ Record format (one JSON line):
   "unique_sources": {N},
   "agents_local": {N},
   "agents_external": {N},
-  "gemini_used": {true|false},
+  "gemini_used": false,
   "confidence": {0.0-1.0},
   "contradictions": {N},
   "open_questions": {N}
@@ -892,15 +887,16 @@ commands surface, don't re-enforce.
 
 When `phase_signal_result.effort == 'high'` for the `research` phase,
 run the FULL swarm regardless of normal triggering rules: 5 local
-agents + 4 external agents + 1 bridge agent, AND force
-`contrarian-researcher` AND `gemini-bridge` to always-on. Normally
-`contrarian-researcher` triggers conditionally when a leading
-recommendation is emerging from initial agents; in high-effort mode it
-runs unconditionally so the final brief always carries an adversarial
-counter-evidence pass. Similarly, `gemini-bridge` normally activates on
-significant architectural questions or when triangulation value is
-high; in high-effort mode it runs unconditionally to provide an
-independent second opinion.
+agents + 4 external agents, AND force `contrarian-researcher` to
+always-on. Normally `contrarian-researcher` triggers conditionally when
+a leading recommendation is emerging from initial agents; in
+high-effort mode it runs unconditionally so the final brief always
+carries an adversarial counter-evidence pass.
+
+The former third-party second-opinion bridge pass is **unavailable,
+skipped** (dropped in v5.10.1 by operator directive). High effort no
+longer has a bridge arm; `gemini_used` is a vestigial stats field
+pinned to `false`.
 
 High effort additionally arms the Phase 5 bounded follow-up loop (max 3
 turns per under-illuminated dimension, budgeted by
@@ -947,7 +943,7 @@ Low effort: inline research only, no agent swarm (existing
   local finding from steering an external agent's question. Attributing the bias
   risk to it left that risk with no control while the text read as though it had
   one.
-- **Graceful degradation:** If MCP tools are unavailable (Tavily, Gemini, MS Learn),
+- **Graceful degradation:** If MCP tools are unavailable (Tavily, MS Learn),
   proceed with available tools and note limitations in brief metadata.
 - **Cost:** Model resolution at Agent-spawn sites is a three-layer fallback:
   brief `phase_signals[<phase>].model` > `profile.phase_models[<phase>]` >