fix(trekplan): drop the "execute with team" path - TeamCreate/TeamDelete no longer exist

Claude Code 2.1.178 removed the TeamCreate and TeamDelete tools, so /trekplan's
"execute with team" handoff could never create a team: it always ended in its own
fallback (sequential execution). The path is removed and the fallback is now the only
behaviour. The handoff no longer offers "execute with team"; if a user asks for it
anyway, /trekplan says there is no team path and executes sequentially. Parallel
implementation stays where it already was: --decompose plus /trekexecute's
multi-session waves. No new orchestration replaces it.

- commands/trekplan.md: TeamCreate/TeamDelete removed from allowed-tools; the offered
  option and the team section are gone.
- agents/planning-orchestrator.md (reference doc): the offered option is gone.
- docs/cc-upgrade-2.1.181-decision-matrix.md still names the team path: a historical
  record, left as written.

End-state gate D-01: open -> closed (defects 7 -> 6 of 7). Suite 1059 (1057/0/2), run
on a clean export of the index.

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

agents/planning-orchestrator.md

@@ -462,7 +462,6 @@ You can:
 - Review the full plan at {plan path}
 - Ask questions or request changes
 - Say "execute" to implement
-- Say "execute with team" for parallel Agent Team implementation
 - Say "save" to keep for later
 ```
 

commands/trekplan.md

@@ -2,7 +2,7 @@
 name: trekplan
 description: Deep implementation planning from a task brief. Requires --brief or --project. Runs parallel specialized agents, optional external research, and adversarial review.
 argument-hint: "--brief <path> | --project <dir> [--fg | --quick | --research <brief> | --decompose <plan> | --export headless <plan>]"
-allowed-tools: Agent, Read, Glob, Grep, Write, Edit, Bash, AskUserQuestion, TaskCreate, TaskUpdate, TeamCreate, TeamDelete
+allowed-tools: Agent, Read, Glob, Grep, Write, Edit, Bash, AskUserQuestion, TaskCreate, TaskUpdate
 ---
 
 # Voyage Local v2.0
@@ -725,7 +725,6 @@ Present a summary to the user:
 You can:
 - Ask questions or request changes to refine the plan
 - Say **"execute"** to start implementing
-- Say **"execute with team"** to implement with parallel Agent Team (if eligible)
 - Say **"save"** to keep the plan for later
 ```
 
@@ -787,22 +786,10 @@ Mark each step complete as you go.
 
 ### "execute with team" / "team"
 
-Before creating a team, verify eligibility:
+There is no team path. Tell the user that parallel team execution is not available
-1. Count implementation steps that are **independent** (no dependency on each other)
+from `/trekplan`, then proceed exactly as for "execute" (sequential, in this
-   AND touch **different files/modules**
+session). Parallel implementation is `--decompose` followed by `/trekexecute`'s
-2. If fewer than 3 independent steps: inform the user and fall back to sequential
+multi-session waves.
-   execution. "The plan has fewer than 3 independent steps — sequential execution
-   is more efficient."
-
-If eligible:
-1. Present the proposed team split: which steps go to which team member
-2. Ask for confirmation: "Create Agent Team with {N} members? (yes/no)"
-3. If confirmed: create the team with `TeamCreate`, assign step clusters to
-   each member. Use `isolation: "worktree"` on each team member agent so they
-   work in isolated git worktrees — this prevents file conflicts during parallel
-   implementation. Coordinate execution and clean up with `TeamDelete` when done.
-4. If `TeamCreate` fails (tool not available): fall back to sequential execution
-   and notify the user
 
 ## Phase 12 — Session tracking