fix(bin): print git switch instead of git checkout for branch commands

.agents/skills/bootstrap-diagnostics/SKILL.md

@@ -30,7 +30,7 @@ When any diagnostic needs captain attention, report the plain consequence and re
   Rerun the printed command; it is idempotent and re-derives every finding.
   A `hit the ...s bound` line means one of those checks is slow or unreachable - most often a remote secondmate host - and the stage stopped rather than letting it wedge; a `lock was no longer held` line means the session that asked for the sweeps no longer owns them, so leave them to the session that does.
 - `TANGLE: <remediation>` - the primary checkout is stranded on a feature branch instead of its default branch; `AGENTS.md` section 8 explains why this guard exists and what it protects.
-  The work is safe on that branch ref; restore the primary to its default branch with the printed `git -C <root> checkout <default>`, then re-validate that branch in a proper worktree.
+  The work is safe on that branch ref; restore the primary to its default branch with the printed `git -C <root> switch <default>`, then re-validate that branch in a proper worktree.
   This is the only sanctioned firstmate-initiated git write to the primary, and it is a non-destructive branch switch that strands nothing.
 - `STARTUP_MEMORY_BUDGET: invalid config/startup-memory-budget - <reason>` - the visible startup-memory budget is not a safe one-line positive decimal file; do not infer the default or propagate it.
   Correct the local primary file, then rerun session start so the normal convergence path can deliver the validated value to secondmate homes.

bin/fm-bootstrap.sh

@@ -84,7 +84,7 @@
 #          secondmate_handoff_resume, x_mode_setup, fleet_sync) while still
 #          printing every read-only detect line
 #          above; the TANGLE line switches to advisory-only wording with no
-#          checkout command. Used by
+#          branch-restore command. Used by
 #          fm-session-start.sh's read-only path when another live session holds
 #          the fleet lock, so a second concurrent session never race-mutates
 #          PR-check artifacts, secondmate homes, pending handoff outboxes,
@@ -1250,7 +1250,7 @@ detect_local_config() {
     if [ "${FM_BOOTSTRAP_DETECT_ONLY:-0}" = 1 ] && [ "${FM_BOOTSTRAP_LOCKED:-0}" != 1 ]; then
       echo "TANGLE: primary checkout on feature branch '$tangle_branch' (expected '$tangle_default'); the work is safe on that ref - read-only session must leave restore work to the session holding the fleet lock"
     else
-      echo "TANGLE: primary checkout on feature branch '$tangle_branch' (expected '$tangle_default'); the work is safe on that ref - restore the primary with: git -C $FM_ROOT checkout $tangle_default, then re-validate the branch in a proper worktree"
+      echo "TANGLE: primary checkout on feature branch '$tangle_branch' (expected '$tangle_default'); the work is safe on that ref - restore the primary with: git -C $FM_ROOT switch $tangle_default, then re-validate the branch in a proper worktree"
     fi
   fi
   crew=

bin/fm-brief.sh

@@ -447,7 +447,7 @@ You are in a disposable git worktree of $REPO, at a detached HEAD on a clean def
 The path check is authoritative: \`git rev-parse --git-dir\` and \`git rev-parse --git-common-dir\` can help inspect the repo, but they do not prove you are outside the primary checkout.
 If the top-level path is the primary checkout or not the worktree you were launched in, STOP - do not branch or commit here - append \`blocked: launched in primary checkout, not an isolated worktree\` to the status file and stop.
 
-1. First action: create your branch: \`git checkout -b fm/$ID\`$SETUP2
+1. First action: create your branch: \`git switch -c fm/$ID\`$SETUP2
 
 # Rules
 $RULE1

bin/fm-guard.sh

@@ -141,7 +141,7 @@ if [ -n "$tangle_branch" ]; then
       printf '●  This read-only session must leave restore work to a session with verified fleet-lock ownership.\n'
     else
       printf "●  Restore the primary to '%s':\n" "$tangle_default"
-      printf '●      git -C %s checkout %s\n' "$FM_ROOT" "$tangle_default"
+      printf '●      git -C %s switch %s\n' "$FM_ROOT" "$tangle_default"
       printf "●  then re-validate '%s' in a proper isolated worktree.\n" "$tangle_branch"
     fi
     printf '●%s\n' "$trule"

docs/configuration.md

@@ -336,7 +336,7 @@ An absent or incompatible `gh-axi` reports `MISSING: gh-axi (install: npm instal
 An absent or incompatible `lavish-axi` reports `MISSING: lavish-axi (install: npm install -g lavish-axi && lavish-axi setup hooks)`.
 An absent or too-old `quota-axi` reports `MISSING: quota-axi (install: npm install -g quota-axi)`; firstmate cannot resolve a profile array without a compatible binary.
 Bootstrap also reports a `TANGLE:` line when `FM_ROOT` is on a named non-default branch; follow the printed checkout remediation rather than treating it as an installable tool problem.
-In a read-only session that did not get the fleet lock, the same line is advisory and omits the checkout command.
+In a read-only session that did not get the fleet lock, the same line is advisory and omits the branch-restore command.
 The locked session-start deferred network stage runs bootstrap's best-effort project clone refresh through `fm-fleet-sync.sh`; [`fm-bootstrap.sh`'s header](../bin/fm-bootstrap.sh) owns the exact clone-refresh overlap, liveness-before-convergence, per-mate concurrency, ordered diagnostic replay, and sequential-fallback contract.
 It emits `FLEET_SYNC:` for skipped refreshes that may matter, recovered self-heals, and `STUCK:` alarms.
 Normal completed runs keep local-only and no-origin skips silent.

tests/fm-session-start.test.sh

@@ -779,7 +779,7 @@ EOF
   assert_not_contains "$out" "drain them with bin/fm-wake-drain.sh" "read-only guard printed a mutating drain instruction"
   assert_not_contains "$out" "After draining queued wakes" "read-only guard printed a drain-then-rearm instruction"
   assert_not_contains "$out" "run bin/fm-watch-arm.sh" "read-only guard printed a mutating watcher-arm instruction"
-  assert_not_contains "$out" "git -C $root checkout main" "read-only bootstrap printed a state-changing checkout remediation"
+  assert_not_contains "$out" "git -C $root switch main" "read-only bootstrap printed a state-changing checkout remediation"
 
   # Detect-only bootstrap diagnostics still ran (the fakebin's PATH excludes
   # tasks-axi, so bootstrap's own read-only tool-detection line fires
@@ -2219,7 +2219,7 @@ EOF
 
   # A re-emit skips the sweeps because it ALREADY ran them, not because it lacks
   # the lock, so it must still own repair rather than deferring to a lock holder.
-  assert_contains "$reemit" "restore the primary with: git -C $root checkout main" \
+  assert_contains "$reemit" "restore the primary with: git -C $root switch main" \
     "--reemit disowned a repair it is entitled to perform"
   assert_not_contains "$reemit" "must leave restore work to the session holding the fleet lock" \
     "--reemit misreported itself as an unlocked read-only session"

tests/fm-tangle-guard.test.sh

@@ -83,11 +83,11 @@ test_guard_banner() {
   out=$(run_guard "$repo")
   assert_contains "$out" "WORKTREE TANGLE" "guard did not alarm on a feature branch in the primary"
   assert_contains "$out" "fm/tangle-aa1" "guard banner did not name the offending branch"
-  assert_contains "$out" "checkout main" "guard banner did not print the restore remediation"
+  assert_contains "$out" "switch main" "guard banner did not print the restore remediation"
   out=$(FM_GUARD_READ_ONLY=1 run_guard "$repo")
   assert_contains "$out" "WORKTREE TANGLE" "read-only guard did not keep the tangle alarm"
   assert_contains "$out" "read-only session must leave restore work" "read-only guard did not explain restore ownership"
-  assert_not_contains "$out" "checkout main" "read-only guard printed a state-changing restore command"
+  assert_not_contains "$out" "switch main" "read-only guard printed a state-changing restore command"
   pass "fm-guard: bordered tangle banner fires only for a feature branch and suppresses repair commands in read-only mode"
 }
 
@@ -112,18 +112,18 @@ test_bootstrap_line() {
   git -C "$repo" checkout -q -B fm/tangle-bb2
   out=$(run_bootstrap "$repo" | grep '^TANGLE:' || true)
   assert_contains "$out" "fm/tangle-bb2" "bootstrap did not report the tangled branch"
-  assert_contains "$out" "checkout main" "bootstrap TANGLE line lacked the restore remediation"
+  assert_contains "$out" "switch main" "bootstrap TANGLE line lacked the restore remediation"
   out=$(FM_ROOT_OVERRIDE="$repo" FM_HOME="$repo" FM_BOOTSTRAP_DETECT_ONLY=1 "$ROOT/bin/fm-bootstrap.sh" 2>/dev/null | grep '^TANGLE:' || true)
   assert_contains "$out" "fm/tangle-bb2" "detect-only bootstrap did not report the tangled branch"
   assert_contains "$out" "read-only session must leave restore work" "detect-only bootstrap did not explain restore ownership"
-  assert_not_contains "$out" "checkout main" "detect-only bootstrap printed a state-changing restore command"
+  assert_not_contains "$out" "switch main" "detect-only bootstrap printed a state-changing restore command"
   pass "fm-bootstrap: TANGLE problem line fires only for a feature branch and suppresses repair commands in detect-only mode"
 }
 
 # --- GUARD 1a: brief isolation assertion ------------------------------------
 
 # The generated ship brief must carry the isolation assertion AHEAD of the
-# `git checkout -b` step, so the crewmate verifies its worktree before branching.
+# `git switch -c` step, so the crewmate verifies its worktree before branching.
 test_brief_assertion_precedes_branch() {
   local home brief iso br
   home="$TMP_ROOT/brief-home"
@@ -140,7 +140,7 @@ test_brief_assertion_precedes_branch() {
   assert_no_grep "they are identical in the primary checkout" "$brief" \
     "brief must not claim the primary checkout has identical git dirs"
   iso=$(grep -n 'launched in primary checkout, not an isolated worktree' "$brief" | head -1 | cut -d: -f1)
-  br=$(grep -n 'git checkout -b fm/' "$brief" | head -1 | cut -d: -f1)
+  br=$(grep -n 'git switch -c fm/' "$brief" | head -1 | cut -d: -f1)
   if [ -z "$iso" ] || [ -z "$br" ]; then
     fail "brief missing assertion ($iso) or branch step ($br)"
   fi