Drop the extension, and give the test suite a front door

Phase 6, the last of the fresh-install spec.

159 scripts lose their .sh: 110 contracts, 47 Vicinae commands, 2 compositor
contracts. A shebang and the executable bit already select the interpreter. The
extension only ever added something that had to stay in sync, and the rename
proved the point twice over in the space of an hour.

The spec's stated risk was Vicinae's script discovery. One script was renamed and
reloaded on its own before the other 46 followed; it came back as
scripts:panama.capture and all 47 resolve. What the probe turned up instead is
that the extension was never only a filename: Vicinae's command IDs embed it, so
every ID changed. Nothing in this repository refers to them, so nothing breaks.
The only trace is Vicinae's metadata.json, whose visited map had two Panama
entries that are now orphaned -- two commands lost their usage ranking and will
earn it back. Worth knowing before anyone renames these again on a machine that
has a keybind pointing at one.

Rewriting the references by exact filename missed two things it structurally
could not see: a name built from a variable, settings-$page.sh, and a glob,
-name '*.sh'. Both were in the contract that counts the generated commands, which
promptly reported 47 expected and 0 found. The mechanical part of a rename is the
part that looks finished.

The three subcommands. panama doctor fronts a health check that already existed
and already ran at the end of every install but could not be reached from a
terminal. panama upgrade re-runs the installer from anywhere. panama test runs
the suite, which had no entry point at all -- 121 files that were the main safety
net in this repository and were invisible in it.

Writing that runner found three tests nothing was running.
calendar_agenda_bridge_test, home_assistant_bridge_test and kdeconnect_bridge_test
are unittest suites without the executable bit, so no contract invoked them and
the first draft of the runner skipped them silently. All three pass, and have
passed unobserved for weeks. The runner collects *_test.py as well now, because a
runner with a blind spot is worse than no runner for the same reason a dependency
checker with one is: it reports PASS.

Six worktrees pruned. Each was re-checked rather than trusted to the spec's list,
and two needed it: panama-commands is not on feat/panama-commands but on
feat/gnome-tweaks-parity, and fix/panama-displays-review reads [ahead 3] -- ahead
of its remote, not of main, with every commit patch-equivalent to landed work.
roadmap-completion stays; it has five commits that are genuinely unlanded. The
branches are left alone: pruning a worktree costs nothing, deleting a branch is a
decision.

121 contracts pass.

Claude-Session: https://claude.ai/code/session_01NvgBuSWB5sE43yWmg21ozj

tests/quickshell/layer-margin-contract

@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+
+# A surface that respects the bar's reserved space must not also subtract it by
+# hand.
+#
+# wlr-layer-shell has three behaviors and only the middle one is subtle:
+#
+#   exclusiveZone > 0   reserve this much space; other surfaces are pushed out
+#   exclusiveZone = 0   reserve nothing, but RESPECT what others reserved
+#   exclusiveZone < 0   reserve nothing and ignore what others reserved
+#
+# Every popover here uses 0, so the compositor has already placed it below the
+# bar before its own margin applies. Adding Theme.barHeight to that margin
+# counts the bar twice. That is not a crash and not a warning -- the panel
+# simply opens lower than intended, which is how the control center spent its
+# life hanging 38px under a bar it was written to sit 2px below, and five other
+# surfaces sat at 48px instead of 12px.
+#
+# The rule is mechanical, so a test can hold it: with exclusiveZone 0, a margin
+# is the GAP, never the gap plus what someone else reserved.
+#
+# Static and read-only.
+
+set -uo pipefail
+
+repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+modules="$repo_dir/config/dot/quickshell/modules"
+
+fail() {
+    printf 'layer margin contract: %s\n' "$1" >&2
+    exit 1
+}
+
+[[ -d "$modules" ]] || fail 'the modules directory is missing'
+
+# The premise: the bar is what reserves space at the top. If that ever changes,
+# the rule below stops being the right rule and this should be revisited rather
+# than kept passing.
+bar="$modules/bar/Bar.qml"
+[[ -r "$bar" ]] || fail 'Bar.qml is missing'
+grep -q 'exclusiveZone: Theme.barHeight' "$bar" \
+    || fail 'the bar no longer reserves its own height, so what popovers should offset by has changed'
+
+violations=""
+checked=0
+
+while read -r file; do
+    [[ -n "$file" ]] || continue
+    grep -q 'PanelWindow' "$file" || continue
+
+    # Only surfaces that respect other zones. A surface with a negative zone is
+    # positioned from the screen edge and SHOULD carry the bar height itself.
+    zone="$(grep -oE 'exclusiveZone:[[:space:]]*-?[0-9]+' "$file" | head -1 | grep -oE '\-?[0-9]+$')"
+    [[ "$zone" == "0" ]] || continue
+    checked=$((checked + 1))
+
+    # Margins only. Theme.barHeight is legitimate elsewhere -- sizing a row to
+    # match the bar, for instance -- so this looks at the placement lines.
+    offenders="$(grep -nE '^[[:space:]]*(margins\.(top|bottom)|top|bottom):.*Theme\.barHeight' "$file" || true)"
+    if [[ -n "$offenders" ]]; then
+        while IFS= read -r line; do
+            violations+="    ${file#$repo_dir/}:${line}"$'\n'
+        done <<<"$offenders"
+    fi
+done < <(find "$modules" -name '*.qml' | sort)
+
+(( checked > 0 )) || fail 'no surfaces with exclusiveZone 0 were found, so this checked nothing'
+
+if [[ -n "$violations" ]]; then
+    printf 'layer margin contract: these surfaces respect the bar'"'"'s reserved space AND add it to their margin, so they open one bar-height too low:\n%s' "$violations" >&2
+    exit 1
+fi
+
+printf 'layer margin contract: PASS (%d surfaces respect the bar without double-counting it)\n' "$checked"