Replace internal `~/projects/extro/cmo/brand/...` paths with neutral
phrasing referring to sol pbc's internal brand canon. The substantive
guidance (canon-permitted code vocabulary vs co-experience language for
owner-facing prose) is preserved.

Replace surveillance-flavored verbs in owner-facing prose ("captures
screen and audio", "screen and audio capture works", "capture source")
with the system-anatomy canon's co-experience phrasing
("experiences your screen and audio along with you"). solstone-linux
is now framed in AGENTS.md project-overview prose as one of the
trinity's observers.

Add a "Brand canon" section to AGENTS.md pointing to
~/projects/extro/cmo/brand/system-anatomy.md, naming the banned
verbs in branded copy, and clarifying that internal architecture
vocabulary (the Capture loop, capture pipeline, module names) is
canon-permitted in code-only contexts and stays as-is.

Internal capture-loop references in AGENTS.md (lines 19, 40, 46, 69)
are unchanged. CLAUDE.md remains a symlink to AGENTS.md and rides
automatically. No source, test, or config changes.

Mirrors the precedent sweeps in the parent solstone repo
(commits ddec60d5 and 929448de).

GNOME's org.freedesktop.ScreenSaver serves only the idle-inhibit
endpoints defined in the FDO idle-inhibit spec (Inhibit, UnInhibit,
SimulateUserActivity). GetActive is not part of the spec, so calling
it on GNOME raises DBusError("This method is not part of the idle
inhibition specification") — not ServiceUnknown/NameHasNoOwner. The
observable-probes rewrite in cbf581d made this surface as a WARN
every 5 s on GNOME Wayland hosts.

Detect GNOME at call time via case-insensitive token-equality match
on XDG_CURRENT_DESKTOP (colon-split, whitespace-stripped) and skip
the FDO branch entirely on GNOME. Non-GNOME desktops are unchanged
— FDO-first, GNOME fallback. The FDO block remains reachable on
KDE/XFCE/Cinnamon/MATE/etc.

Surfacing trail: lode 7ppx4a7g. Decision to go with
GNOME-as-early-skip (option b) recorded 2026-04-22.

Co-Authored-By: OpenAI Codex <codex@openai.com>

activity.py and screencast.py hid DBus probe failures behind broad
`except Exception: pass` and `return <literal>` fallbacks. Parser bugs,
bus-daemon dropouts, and timeouts all looked identical to "service not
present", which dropped operator signal and could silently flip
probe_activity_services() into always-capture mode when a real backend
was present but introspection broke.

Fix: inherit the doctor.check_portal pattern from 1629914. Service
presence probing now asks the bus daemon (org.freedesktop.DBus at
/org/freedesktop/DBus) whether a well-known name is owned via
NameHasOwner instead of introspecting each target service path. The
bus-daemon XML has no hyphenated members, so the parser bug does not
apply, and the code can distinguish "not registered" from "probe
broke".

This fixes seven sites: activity.probe_activity_services now uses
NameHasOwner against the bus daemon; activity.is_screen_locked narrows
both the FDO and GNOME fallback branches; activity.is_power_save_active
does the same for Mutter and KDE Solid; activity.get_monitor_geometries_kscreen
narrows its catch to concrete DBus/introspection failures; and
screencast.Screencaster._close_session now warns with the portal session
path instead of silently swallowing close failures.

One design choice is intentional: backend branches in the lock/power
fallback chains and KScreen suppress WARN logs when DBusError.type is
org.freedesktop.DBus.Error.ServiceUnknown or
org.freedesktop.DBus.Error.NameHasNoOwner. Without that, asymmetric
desktops such as vanilla GNOME (no KDE Solid) or KDE (no Mutter
DisplayConfig) would emit thousands of warnings per day from the 5s poll
loop. Any other probe failure stays loud: parser bugs, bus failures,
non-missing DBusError values, and close-session failures still warn.
_close_session and _name_has_owner log unconditionally because closing a
known session should work, and NameHasOwner returns False rather than
raising for truly missing services.

This closes the follow-up called out in the footer of 1629914, and adds
regression coverage for parser failures, broken backends, silent missing
services, and close-session logging.

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