Phase 0: X11 paths + measurement-instrument inventory captured

Live Plasma X11 session on ohm probed over SSH; substrate is
healthy (xorg-server 21.1.22 + Mesa 26.0.5 / Panfrost,
modesetting in-server, all 7 needed X protocol extensions live).
Evidence in phase0_evidence/x11_inventory_2026-05-03/ — five raw
captures + inventory.md summary. Worklist deliverables 2 + 4
flipped to done with operator-action checklist for the remaining
gating items (no non-compositing WM installed today; six
candidates one pacman -S away, openbox recommended).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

worklist.md

@@ -42,18 +42,16 @@ inventory and baseline-anchor work below.
   via SSH. Captures package versions, kernel, kwin_wayland
   PID + cmdline, governor, services, browser binary versions,
   test asset paths, thermal_zone temps.
-- [ ] Inventory of available X11 paths on ohm:
-  - Installed packages: `xorg-server`, `xorg-xinit`,
-    `xorg-xrandr`, drm/dri stack, `mesa-x11` if separated.
-  - SDDM-advertised sessions: list `/usr/share/xsessions/*`.
-  - Alternate WMs available (openbox, fluxbox, xfwm4, i3,
-    etc.) — what's installed, what'd need installing.
-  - Whether modesetting Xorg driver (`xf86-video-modesetting`)
-    is the active driver path on rockchip-drm, vs an older
-    armsoc/fbdev driver.
-  - XWayland availability and version (relevant only as a
-    third comparison axis — primary X11 cells are NATIVE
-    Xorg, not XWayland).
+- [x] Inventory of available X11 paths on ohm. Captured
+  2026-05-03 in `phase0_evidence/x11_inventory_2026-05-03/`
+  (raw `02_x11_paths.txt` + summary `inventory.md` § "Deliverable 2").
+  Verdict: xorg-server 21.1.22 + Mesa 26.0.5 / Panfrost healthy,
+  modesetting (in-server) is sole DDX, only `kwin_x11` WM
+  installed today, six WM candidates available in extra,
+  Plasma X11 + Plasma Wayland + Weston are the SDDM-advertised
+  sessions. Operator action: `pacman -S` a non-compositing WM
+  (recommend openbox) and create/switch to its SDDM session
+  before without-KWin cells can run.
 - [ ] **NEW: Browser X11-overlay-path inventory.** Per
   `phase0_findings.md` § "Open questions": determine whether
   Brave 147 ozone-x11, chromium-fourier 149 ozone-x11, and
@@ -69,14 +67,18 @@ inventory and baseline-anchor work below.
   from "do browsers use it." If mpv hits Plane 39 NV12 cleanly
   but browsers don't, the answer is "X11 path is fast, but
   the browsers don't take advantage of it."
-- [ ] Inventory of X11-side measurement instruments. Available
-  options: `xtrace` (X protocol tracer), `xev` (event viewer),
-  `xprop` (window properties), `xrandr --verbose` (output
-  state), `glxinfo`, `compton-trans` for compositor detection,
-  perf on Xorg PID. Frame-timing under X11 typically uses
-  `XPresent` notify events or `INTEL_swap_event` GLX
-  extension equivalents — what's available on rockchip is
-  open.
+- [x] Inventory of X11-side measurement instruments. Captured
+  2026-05-03 in `phase0_evidence/x11_inventory_2026-05-03/`
+  (raw `04_measurement_instruments.txt` + summary `inventory.md`
+  § "Deliverable 4"). Live X server supports all 7 needed
+  extensions (Composite, DAMAGE, DRI3, Present, RANDR, SYNC,
+  XVideo). Tools installed: xprop, xdpyinfo, xset, glxinfo,
+  drm_info, perf, mpv, libxcb-present. Tools missing-but-in-extra:
+  xrandr CLI, xev, xinput, xwininfo, xkill, sysprof — one
+  `pacman -S` away. AUR-only: X-protocol `xtrace` (the
+  `/usr/bin/xtrace` from glibc is a syscall tracer, unrelated);
+  optional, matrix doesn't strictly need protocol traces.
+  perf_event_paranoid=2 — set to 1 once for unattended runs.
 - [ ] **A1 baseline: in-session Wayland-with-KWin anchor.**
   Mandatory per the governing rule. 3 reps minimum (variance
   is a real concern on this hardware per the predecessor