Add audio and region recording; make routine CI manual (#25)

The top-bar recorder previously saved a full monitor without sound. It now lets you select a region within one monitor and choose system audio, microphone audio, or both. Audio remains off by default, and recordings with audio are saved as VP8/Opus WebM files. The portal still controls screen access and cancellation; stopping from the bar or ending the video stream finishes the recording, including its audio tracks.

Region selection accounts for fractional display scales and negative monitor coordinates. The picker keeps its action buttons visible while the display list and recording options scroll together. The picker, dependency lists, and recording documentation now explain the available choices and the slurp and audio requirements.

Routine pushes and pull requests no longer start CI runners. Workspace checks and website deployment are manual, while release checks run when requested manually, through a version tag, or through a PR labeled `release`. Publishing still requires a pushed version tag. This also fixes release asset checksums by normalizing RPM filenames before generating the checksum file.

Validated locally with a release build, portal and shell recorder tests, formatting, Clippy, actionlint, packaging tests, and mocked publishing checks. Media tests encoded and decoded cropped video with audio, checked that video termination finishes live audio, and exercised system, microphone, and combined capture against a private PipeWire-Pulse server. Mixed recordings must contain both fixture frequencies, with negative controls for either missing source. The picker was also checked on 800 × 600 and 800 × 400 desktops and opened in a live nested window.

portal/src/recording_region.rs

@@ -0,0 +1,137 @@
+//! Map an approved logical recording region into the upright video stream.
+use crate::recording::Crop;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) struct Region {
+    pub(crate) x: i32,
+    pub(crate) y: i32,
+    pub(crate) width: i32,
+    pub(crate) height: i32,
+}
+
+impl Region {
+    pub(crate) fn parse(value: &str) -> Result<Self, String> {
+        let (position, size) = value.trim().split_once(' ').ok_or("Invalid region selection")?;
+        let (x, y) = position.split_once(',').ok_or("Invalid region position")?;
+        let (width, height) = size.split_once('x').ok_or("Invalid region size")?;
+        let number = |value: &str| value.parse::<i32>().map_err(|_| "Invalid region coordinate".to_owned());
+        let region = Self {
+            x: number(x)?,
+            y: number(y)?,
+            width: number(width)?,
+            height: number(height)?,
+        };
+
+        if region.width <= 0
+            || region.height <= 0
+            || region.x.checked_add(region.width).is_none()
+            || region.y.checked_add(region.height).is_none()
+        {
+            return Err("Invalid region bounds".into());
+        }
+
+        Ok(region)
+    }
+
+    pub(crate) fn crop(self, output: Self, physical: (u32, u32)) -> Result<Crop, String> {
+        let x = i64::from(self.x) - i64::from(output.x);
+        let y = i64::from(self.y) - i64::from(output.y);
+        let end_x = x + i64::from(self.width);
+        let end_y = y + i64::from(self.height);
+
+        if self.width <= 0
+            || self.height <= 0
+            || output.width <= 0
+            || output.height <= 0
+            || x < 0
+            || y < 0
+            || end_x > i64::from(output.width)
+            || end_y > i64::from(output.height)
+            || physical.0 == 0
+            || physical.1 == 0
+            || physical.0 > i32::MAX as u32
+            || physical.1 > i32::MAX as u32
+        {
+            return Err("Select a region entirely inside the chosen display".into());
+        }
+        // Round inward so pixels outside the selected logical rectangle never
+        // enter the recording, including at fractional output scales.
+        let near = |value: i64, pixels: u32, logical: i32| {
+            (value * i64::from(pixels) + i64::from(logical) - 1) / i64::from(logical)
+        };
+        let far = |value: i64, pixels: u32, logical: i32| value * i64::from(pixels) / i64::from(logical);
+        let left = near(x, physical.0, output.width);
+        let top = near(y, physical.1, output.height);
+        let end_x = far(end_x, physical.0, output.width);
+        let end_y = far(end_y, physical.1, output.height);
+
+        if end_x <= left || end_y <= top {
+            return Err("The selected region is smaller than one output pixel".into());
+        }
+
+        Ok(Crop {
+            left: left as i32,
+            top: top as i32,
+            right: (i64::from(physical.0) - end_x) as i32,
+            bottom: (i64::from(physical.1) - end_y) as i32,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn region_mapping_handles_negative_origins_and_fractional_scales() {
+        let output = Region::parse("-1920,20 1920x1080").unwrap();
+        let selected = Region::parse("-1919,21 100x50").unwrap();
+        assert_eq!(
+            selected.crop(output, (2400, 1350)).unwrap(),
+            Crop {
+                left: 2,
+                top: 2,
+                right: 2274,
+                bottom: 1287
+            }
+        );
+        assert_eq!(
+            output.crop(output, (2880, 1620)).unwrap(),
+            Crop {
+                left: 0,
+                top: 0,
+                right: 0,
+                bottom: 0
+            }
+        );
+        assert!(
+            Region::parse("-1921,20 100x50")
+                .unwrap()
+                .crop(output, (2400, 1350))
+                .is_err()
+        );
+        assert!(
+            Region::parse("-100,20 200x50")
+                .unwrap()
+                .crop(output, (2400, 1350))
+                .is_err()
+        );
+    }
+
+    #[test]
+    fn region_selection_rejects_empty_overflow_and_malformed_bounds() {
+        for value in ["", "1,2 0x20", "1,2 -1x20", "2147483647,0 2x20", "1,2 20x30 extra"] {
+            assert!(Region::parse(value).is_err(), "{value}");
+        }
+        assert!(
+            Crop {
+                left: -1,
+                top: 0,
+                right: 0,
+                bottom: 0
+            }
+            .validate()
+            .is_err()
+        );
+    }
+}