fix: communication scrcpy — drop scrcpy from apt PACKAGES (not in Debian/Ubuntu repos by default), install via apps/media/scrcpy.sh

AGENT_TODO.md

@@ -16,6 +16,8 @@ summary (newest last).
 
 ## Done
 
+- **2026-08-13** — Fix scrcpy apt install on the live box: preinstall `apt install` failed with `Unable to locate package scrcpy` (Debian/Ubuntu need contrib/universe for `scrcpy`, and the apt build is older anyway). Removed `scrcpy` from `preinstall.sh` PACKAGES (kept `adb`); `scrcpy` now installs via the existing optional app `apps/media/scrcpy.sh` (GitHub latest, bundles adb) — docs (POS.md, howto/communication.md) and the tool's deps-guard error reworded to lead with that path. Re-verified: `bash -n`, stub suite 21/21, `make gen && make check` green.
+
 - **2026-08-13** — `pos communication scrcpy` (`bin/pos-communication-scrcpy`): wrapper over scrcpy+adb for Android mirroring/control. Subcommands: bare `scrcpy` (mirror — config defaults + verbatim pass-through of any scrcpy flag; no device → friendly error + hints), `devices` (`adb devices -l`), `record [file] [--headless]` (default `$SCRCPY_RECORD_DIR/<device>_<date>.mp4`, `--headless` = `--no-playback` for headless servers), `tcpip [port]` (USB→wireless switch + prints `connect` with the auto-detected device IP), `connect <ip[:port]>` (adb connect + mirror `-s`), `push` (default `/sdcard/Download` = scrcpy's own default), `pull`, `screenshot` (`adb exec-out screencap -p` → PNG in RECORD_DIR), `info` (model/android/sdk/serial via getprop). Config scope `scrcpy` (`~/.config/linux_post_install/scrcpy.env`, `pos config scrcpy`): `SCRCPY_SERIAL/MAX_SIZE/MAX_FPS/BIT_RATE/FULLSCREEN/RECORD_DIR/PUSH_TARGET/EXTRA_FLAGS`, env-var precedence. Deps `scrcpy` + `adb` added to preinstall PACKAGES; docs note the apt build is older and point to the existing `apps/media/scrcpy.sh` app installer (GitHub latest, bundles adb) — researched 2026 releases (current v4.1). Conventions: `# POS:`/`# POS_SUBCMDS:`/`# POS_CONFIG:` headers, deps guards before `-h|--help`, no stdin → no INTERACTIVE_CMDS. Verified: `bash -n`, stub-PATH suite `/tmp/opencode/scrcpy-run-test.sh` 21/21 green (fake adb/scrcpy echo-args, HOME isolation, env/file precedence, rc paths, screenshot bytes), `make gen && make check` green, dispatch via `pos communication scrcpy --help`. Docs: POS.md communication table + detail block, howto/communication.md section, HOWTO.md index + env row, AGENT_Context Common Tasks row + gen'd tree/dispatch/filetable.
 
 - **2026-08-13** — Entertainment-module hardening (approved Tier 1 + Tier 2): delivery moved to `notify_send` (platform follows `NOTIFY_PLATFORM`, default Telegram) via `lib/notify.sh` sourced by `bin/pos-entertainment-send`; a **last-run state** is recorded per plugin (`~/.local/share/linux_post_install/entertainment/last/<plugin>` — rc + timestamp) on every non-`--print` run and shown by `pos entertainment status`, which also lists installed-but-not-enabled plugins; a send that fails **while fired by a timer** (gated on `$INVOCATION_ID`) additionally notifies the configured platforms. New **message-safe plugin lib** `lib/entertainment-plugin-lib.sh` (defines only `plugin_*`, never writes stdout — the stdout contract stays "message only"): `plugin_load_config` (entertainment.env + env precedence), `plugin_have`, `plugin_require`, `plugin_err`, `plugin_http_json <url> [--key <jq>] [-H <header>]` (curl `--max-time 20 --retry 2`); `weather`/`joke`/`gold` refactored onto it. `pos entertainment config` gains `get|unset|ls|edit` (edit via the shared `pos config` UI — added to `INTERACTIVE_CMDS`). **Tier 2**: new shared lib `lib/user-timers-lib.sh` (only `ut_*`: `ut_interval_to_oncalendar`, `ut_interval_label`, `ut_unit_name`, `ut_write_unit_pair` incl. `TimeoutStopSec=5s` + `Persistent` + network-online deps, `ut_ensure_linger`, `USER_SYSTEMD_DIR`) dedupes the systemd user-timer machinery between `lib/entertainment-lib.sh` and `lib/scheduler-lib.sh` (the latter's `sched_*` duplicates deleted; both source it; collides-with-nothing). `install.sh` Phase 2 lib list += the two new libs; SCRIPTS.md/DEV.md/POS.md/howto/entertainment.md/AGENT_Context updated (hand-maintained lib rows: entertainment-lib 354→311, scheduler-lib 830→760, +112 user-timers-lib, +67 plugin lib). Verified: `bash -n` everywhere; smoke-tested in an isolated `HOME=/tmp/enttest` (status, config get/set/unset/ls, send path rc=0, failing plugin records rc=1, error-case message hygiene); `make gen && make check` green.