fix(als-brightness): center slider windows and ship the tuned node defaults

[ZhangDM-520]

Plugin

• Id: zhangdm/als-brightness
• New plugin
• Update to an existing plugin (version bumped in plugin.toml)

What it does

Fixes the threshold sliders' calibration and adopts the maintainer's tuned curve as the shipped default (0.5.0 → 0.6.0):

• Slider windows are now centered on their default. The old [d/3, 3d] window parked the default at 25 % of the linear track, which read as a mis-calibrated slider. Every window is now [0, 2·d] (brightness) / d ± 500 (temperature), so the value shown at rest sits at the exact midpoint of the track — with one documented exception: node 1 defaults to 0, which cannot be centered on a non-negative axis (thr_brightness_01 gets [0, 2]).
• New shipped node positions (the maintainer's hand-tuned values, 2026-10): brightness raw counts 0, 1, 3, 10, 33, 61, 560, 1680, 4800, 14200; temperature 2000 … 6000. The fixed outputs are unchanged (20.8 % … 100 %, 5100 … 6500 K), so the curve's shape is the same and only where each step applies moves. A fresh install now behaves like the maintainer's tuned machine.
• The 16384 sensor-ceiling cap on slider windows is dropped: readings above the sensor's 16383 ceiling are unreachable, so a threshold up there is inert — where a node sits is the owner's judgement.
• A drift-check property pins the requirement: all 20 sliders assert default == (min + max) / 2, with the thr_brightness_01 exception named in the test.

External dependencies

• noctalia (the manifest dependencies entry): unchanged from 0.5.0 — short-lived noctalia msg commands (keyboard-backlight-set, brightness-set, config-reload, status) via an argv table. No network. This change touches no additional processes.

Every filesystem write, accounted: unchanged from 0.5.0 — profile.json and als-brightness.log in the plugin data dir, and (with colortemp on) the night-light settings.toml text splice. This change writes nothing new.

Every spawned process, accounted: the four noctalia msg commands above; nothing else.

Testing

• Tested on Niri

• Tested on Hyprland

• Tested on Sway

• Tested on another compositor:

• Noctalia version tested against: v5.2.1

• Plugin API level: 24

• Offline gate: 1344 checks across 10 suites, 0 failures (was 1303 — the curve and settings-spec suites grew for the rebaseline), run with ./run-tests.sh. The settings-surface drift check (manifest rows, translations and code constants must agree) is green at 66 rows.

• Drift-check property added: every slider's default is asserted to sit at the exact midpoint of [min, max], with thr_brightness_01 (default 0) named as the single exception.

• Validated with this repo's CI validator: validate-plugins.py reports no errors for als-brightness/.

• The maintainer's machine carries these values as settings overrides today; the sliders were exercised there while hand-tuning them, and the screenshots in the issue thread show the exact values shipped here.

Screenshots / Videos

None: this update changes slider ranges and defaults in the existing settings sheet — no new visual surface. (Settings-page screenshots were shared with the maintainer during development.)

Checklist

Ready-for-review requirement: Every box in this section must be checked. If any statement is not true, keep the pull request as Draft. An explanation does not replace a required check.

• The directory name matches the part of id after the / in plugin.toml exactly.
• It ships plugin.toml, README.md, thumbnail.webp, and translations/en.json.
• README.md follows the
  README template, documents
  every entry id and dependency, and includes exact panel IPC commands and launcher prefixes where applicable.
• thumbnail.webp is present and relevant; for a new plugin I created it with the thumbnail generator, and for an update I regenerated it with the generator if the visual identity or user-facing appearance changed.
  (Unchanged: the card identity did not change — this update alters slider ranges/defaults in the settings sheet.)
• version follows semver and is bumped in this PR; plugin_api is the oldest API level this plugin requires.
• Every non-English translation in this PR uses a locale supported by Noctalia core, and I can read, write, and
  understand that language well enough to review and maintain it (no unreviewed machine/LLM translations).
  (No translation files change in this PR.)
• I did not edit catalog.toml; CI generates it.
• This PR touches exactly one plugin directory.

Code review attestation

Plugins run as trusted, unsandboxed Luau in the user's session. Confirm:
Ready-for-review requirement: Every attestation below must be checked.

• The code is readable and not obfuscated, minified, or generated.
• It does not download and execute remote code.
• Every network call, filesystem write, and spawned process is something the description above accounts for.
• I have the right to publish this code under the license declared in plugin.toml.
  (The maintainer is the plugin's author; MIT as declared.)