Fix: Adopt a Terra the machine already trusts

The repository audit made any Terra that is not Panama's own pinned form a
trust-root failure, and status 78 then stopped every stage before it ran. A
machine that installed Terra the way Terra documents it -- terra-release's own
repo file, a metalink, the key at its stock path -- was classified hostile and
had no way back, because install_terra_repository refused to touch a machine
terra-release had already reached. A gate with no door.

The trust root is the signing key, and that key is byte-for-byte the
fingerprint this repository reviewed and pinned, with every signature check
already on. So verify the fingerprint and adopt the configuration into the
pinned form instead of refusing it. Adoption needs no network and no DNF, it
runs before any other transaction in the stage, and it is repeatable, which it
has to be: terra-release owns that file and restores it on update.

Adoption stays narrow. The pinned fingerprint must match both the reviewed key
and the key the machine actually verifies against, the gpgkey must be a local
file under the system trust directory, and the endpoint must be one Terra
itself serves -- so the reviewed baseurl or the reviewed metalink host, now
pinned as TERRA_METALINK_BASEURL. An unknown key, a redirected baseurl, a
second enabled Terra, or a disabled signature check is still a hard refusal.

A refusal also stops less than it did. It suppresses the stages that open DNF
and the migrations, which may run a transaction of their own, and the run still
exits 78. It no longer stops link-dotfiles, link-skills or link-user, which
read no repository and install no package. Exiting before them is what left
this laptop with a stale ~/.claude/skills and no shipped skill reachable.

Also stub ensure_flathub_remote in the extras contract, which has been failing
since that call was added to install_extra_category without one.

Claude-Session: https://claude.ai/code/session_01PeTrG9dGY89UWuhGm4Pr1s

install

@@ -149,20 +149,37 @@ record_packages_hash() {
 }
 
 # Repository trust is checked before the installer can reach its bootstrap DNF.
-# Status 78 is reserved for a trust-root failure and is propagated unchanged so
-# no later stage, especially install-hardware, can invoke DNF with that repo.
+# Status 78 is reserved for a trust-root failure. It suppresses every stage that
+# opens DNF -- install-hardware included, which would otherwise pull drivers
+# through the very repository in doubt -- and the run still exits 78 at the end.
+#
+# It suppresses nothing else. Linking dotfiles, skills and user content reads no
+# repository and installs no package, and a machine whose Terra is in question
+# still wants its configuration. Refusing the safe work because the unsafe work
+# is unavailable does not make the machine safer, it just leaves the machine
+# unconfigured with no way to fix itself. Exiting here instead meant link-skills
+# never ran on a machine whose Terra was merely unadopted, so ~/.claude/skills
+# stayed the whole-directory symlink it had been before skills were linked one
+# by one, and not one shipped skill was reachable.
 TERRA_TRUST_FAILURE_STATUS=78
+DNF_STAGES=(install-packages change-settings install-hardware)
+package_trust_refused=0
+
+stage_opens_dnf() {
+  local candidate="$1" dnf_stage
+  for dnf_stage in "${DNF_STAGES[@]}"; do
+    [[ "$candidate" == "$dnf_stage" ]] && return 0
+  done
+  return 1
+}
+
 trust_preflight="$PANAMA_PATH/setup/scripts/install-packages"
 if [[ ! -x "$trust_preflight" ]]; then
   printf 'install: package repository trust preflight is unavailable\n' >&2
-  exit "$TERRA_TRUST_FAILURE_STATUS"
-fi
-if "$trust_preflight" --trust-preflight; then
-  :
-else
-  trust_status=$?
+  package_trust_refused=1
+elif ! "$trust_preflight" --trust-preflight; then
   printf 'install: package repository trust preflight failed\n' >&2
-  exit "$trust_status"
+  package_trust_refused=1
 fi
 
 # ── The interview ────────────────────────────────────────────────────────────
@@ -182,7 +199,7 @@ fi
 # Gated exactly like the interview itself: under --upgrade no questions are
 # asked, so nothing here is used, and a machine that cannot install gum must
 # not have that stop an upgrade that never needed it.
-if (( ! UPGRADE )); then
+if (( ! UPGRADE && ! package_trust_refused )); then
   bootstrap=()
   command -v gum >/dev/null 2>&1 || bootstrap+=(gum)
   # The probe tools serve only the hardware questions, which a server is never
@@ -349,6 +366,10 @@ for stage in "${STAGES[@]}"; do
   script="$PANAMA_PATH/setup/scripts/$stage"
   [[ -x "$script" ]] || continue
   printf '\n=== %s ===\n' "$stage"
+  if (( package_trust_refused )) && stage_opens_dnf "$stage"; then
+    echo "Skipped: the package repository trust check refused package work."
+    continue
+  fi
   if [[ "$stage" == install-packages ]]; then
     package_state_status=0
     package_start_hash="$(hash_packages)" || package_state_status=2
@@ -374,9 +395,12 @@ for stage in "${STAGES[@]}"; do
     fi
   else
     stage_status=$?
+    # A configuration change between the preflight and this stage. Suppress the
+    # remaining DNF stages, keep the safe ones, and carry the status to the end.
     if [[ "$stage" == install-packages && "$stage_status" -eq "$TERRA_TRUST_FAILURE_STATUS" ]]; then
       printf '!!! %s stopped on an untrusted package repository\n' "$stage" >&2
-      exit "$stage_status"
+      package_trust_refused=1
+      continue
     fi
     failed+=("$stage")
     printf '!!! %s failed\n' "$stage" >&2
@@ -402,8 +426,16 @@ done
 # written for -- and baselining would skip every one of them forever. Every
 # migration is self-guarding and a no-op where it does not apply, so running
 # them is the safe direction.
+#
+# Held back when package work was refused. A migration is free to run a DNF
+# transaction -- the ChatGPT package replacement does exactly that -- so the
+# repositories have to be trustworthy before any of them is allowed to run.
+# They are not marked applied either, so the next run still has them pending.
 migrate="$PANAMA_PATH/bin/panama-migrate"
-if [[ -x "$migrate" ]]; then
+if (( package_trust_refused )) && [[ -x "$migrate" ]]; then
+  printf '\n=== migrations ===\n'
+  echo "Skipped: the package repository trust check refused package work."
+elif [[ -x "$migrate" ]]; then
   printf '\n=== migrations ===\n'
   if (( UPGRADE )) || [[ -d "$STATE_DIR/migrations" ]]; then
     "$migrate" run || failed+=(migrations)
@@ -451,6 +483,17 @@ else
   retry='./install'
 fi
 
+# Reported last and on its own, because it is not an ordinary stage failure:
+# everything safe did run, and what did not run is named rather than buried in a
+# list. The exit status stays 78 so a caller can still tell the two apart.
+if (( package_trust_refused )); then
+  printf 'Package work was refused: the Terra repository configuration on this\n' >&2
+  printf 'machine is not one Panama can verify. Skipped: %s\n' "${DNF_STAGES[*]}" >&2
+  printf 'Everything that touches no repository was still applied.\n' >&2
+  printf 'Inspect it with: panama diagnose\n' >&2
+  exit "$TERRA_TRUST_FAILURE_STATUS"
+fi
+
 if (( ${#failed[@]} == 0 )); then
   if (( UPGRADE )); then
     echo "Panama is up to date."