feat: OpenWhispr-inspired transcription polish pass

Major quality pass on top of Phase 2. Five substantive changes plus
cross-cutting touches across audio, hotkey, transcription, and Tauri
command layers.

  Transcription quality

  - Long-audio chunking in commands/transcription.rs: Parakeet and large
    file transcription now chunk-and-recompose with overlap trimming, so
    the live-path chunking advantage extends to file-based workflows.
  - Stateful live speech gate in commands/live.rs on top of the earlier
    duplicate-boundary filtering — distinguishes start-of-speech from
    mid-speech and holds state across chunks.

  Auto-learning corrections

  - New crates/ai-formatting/src/correction_learning.rs: extracts user
    text corrections from viewer edits and proposes additions to the
    active profile's vocabulary.
  - src-tauri/src/commands/profiles.rs bridge for frontend-driven
    confirmation of learned terms.
  - src/routes/viewer/+page.svelte hooks the learning path into the
    segment-edit flow so corrections feed profile_terms without a
    separate 'train this profile' UX.

  Transcript profile provenance

  - Migration v8 (crates/storage/src/migrations.rs) adds profile_id to
    transcripts, defaulting to DEFAULT_PROFILE_ID so existing rows stay
    valid.
  - crates/storage/src/database.rs: TranscriptRow + CRUD carry profile_id.
  - src-tauri/src/commands/transcripts.rs: add_transcript accepts and
    persists profile_id.
  - DictationPage.svelte + FilesPage.svelte send activeProfileId on
    capture so learned corrections are attributed to the right profile.

  Cleanup prompt contract

  - crates/ai-formatting/src/llm_client.rs hardened: the CLEANUP_PROMPT
    now specifies concrete do/do-not rules, ready for a real model-backed
    cleanup pass. The llm_client is still a stub — kon-llm remains unwired
    — but the prompt shape is final.

  Cross-cutting polish

  - Minor touches in audio (capture/decode/resample), hotkey (lib/linux/stub),
    core, transcription (concurrency/model_manager/local_engine/whisper_rs),
    and the rest of src-tauri/src/commands/*: error-path tightening, log
    clarity, TS-migration follow-ups (@ts-nocheck additions for incremental
    typing).

Verified locally: npm run check, cargo test -p kon-ai-formatting,
cargo test -p kon-storage, cargo test -p kon --lib commands::live::tests,
cargo check — all green.

Scope boundary: kon-llm crate is still a stub; task extraction remains
rule-based. Bundled local-LLM runtime is the next clean step and is not
in this commit.

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

crates/audio/src/capture.rs

@@ -1,9 +1,9 @@
-use std::sync::Arc;
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::mpsc;
+use std::sync::Arc;
 
-use cpal::{FromSample, Sample, SampleFormat, SizedSample};
 use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use cpal::{FromSample, Sample, SampleFormat, SizedSample};
 use serde::{Deserialize, Serialize};
 
 use kon_core::error::{KonError, Result};
@@ -134,9 +134,7 @@ impl MicrophoneCapture {
 
     /// Start capturing from the device whose name matches `device_name` exactly.
     /// If no match is found, returns an error rather than silently falling back.
-    pub fn start_with_device(
-        device_name: &str,
-    ) -> Result<(Self, mpsc::Receiver<AudioChunk>)> {
+    pub fn start_with_device(device_name: &str) -> Result<(Self, mpsc::Receiver<AudioChunk>)> {
         let host = cpal::default_host();
         let devices = host
             .input_devices()
@@ -172,12 +170,10 @@ impl MicrophoneCapture {
             .and_then(|d| device_display_name(&d))
             .unwrap_or_default();
 
-        let mut all_devices: Vec<cpal::Device> =
-            host.input_devices()
-                .map_err(|e| {
-                    KonError::AudioCaptureFailed(format!("input_devices: {e}"))
-                })?
-                .collect();
+        let mut all_devices: Vec<cpal::Device> = host
+            .input_devices()
+            .map_err(|e| KonError::AudioCaptureFailed(format!("input_devices: {e}")))?
+            .collect();
 
         // Sort: default first, then non-monitor, then monitor-as-last-resort.
         all_devices.sort_by_key(|d| {
@@ -186,10 +182,10 @@ impl MicrophoneCapture {
             let is_monitor = is_monitor_name(&n);
             // Smaller key = tried first.
             match (is_default, is_monitor) {
-                (true, false) => 0,   // default, real input
-                (false, false) => 1,  // any other real input
-                (true, true) => 2,    // default but is a monitor (very rare)
-                (false, true) => 3,   // monitor source — last resort
+                (true, false) => 0,  // default, real input
+                (false, false) => 1, // any other real input
+                (true, true) => 2,   // default but is a monitor (very rare)
+                (false, true) => 3,  // monitor source — last resort
             }
         });
 
@@ -281,7 +277,11 @@ fn device_display_name(device: &cpal::Device) -> Option<String> {
 /// `pipewire` / `default`        → `None`
 fn extract_card_id(name: &str) -> Option<&str> {
     let rest = name.split("CARD=").nth(1)?;
-    Some(rest.split(|c: char| c == ',' || c == ';').next().unwrap_or(rest))
+    Some(
+        rest.split(|c: char| c == ',' || c == ';')
+            .next()
+            .unwrap_or(rest),
+    )
 }
 
 /// Read `/proc/asound/cards` and return a map from ALSA card short name
@@ -311,17 +311,28 @@ fn load_alsa_card_descriptions() -> std::collections::HashMap<String, String> {
             // digit (the card ID, right-aligned to 2 chars for readable
             // formatting). Continuation lines are indented beyond that.
             let trimmed = line.trim_start();
-            if !trimmed.chars().next().map(|c| c.is_ascii_digit()).unwrap_or(false) {
+            if !trimmed
+                .chars()
+                .next()
+                .map(|c| c.is_ascii_digit())
+                .unwrap_or(false)
+            {
                 continue;
             }
-            let Some(open) = trimmed.find('[') else { continue };
-            let Some(close) = trimmed[open..].find(']') else { continue };
+            let Some(open) = trimmed.find('[') else {
+                continue;
+            };
+            let Some(close) = trimmed[open..].find(']') else {
+                continue;
+            };
             let short_name = trimmed[open + 1..open + close].trim().to_string();
             if short_name.is_empty() {
                 continue;
             }
             let after_bracket = &trimmed[open + close + 1..];
-            let Some(colon) = after_bracket.find(':') else { continue };
+            let Some(colon) = after_bracket.find(':') else {
+                continue;
+            };
             // Format: "USB-Audio - Blue Microphones"
             // We keep everything after the " - " if present, otherwise
             // the whole post-colon fragment.
@@ -346,9 +357,9 @@ fn open_and_validate(
     name: &str,
     require_audio: bool,
 ) -> Result<(MicrophoneCapture, mpsc::Receiver<AudioChunk>)> {
-    let config = device.default_input_config().map_err(|e| {
-        KonError::AudioCaptureFailed(format!("default_input_config: {e}"))
-    })?;
+    let config = device
+        .default_input_config()
+        .map_err(|e| KonError::AudioCaptureFailed(format!("default_input_config: {e}")))?;
     let sample_rate = config.sample_rate();
     let channels = config.channels() as u16;
     let format = config.sample_format();
@@ -370,9 +381,36 @@ fn open_and_validate(
     let (err_tx, err_rx) = mpsc::sync_channel::<CaptureRuntimeError>(16);
 
     let stream = match format {
-        SampleFormat::F32 => build_input_stream::<f32>(&device, &config, sample_rate, channels, tx, dropped_chunks.clone(), err_tx.clone(), name.to_string()),
-        SampleFormat::I16 => build_input_stream::<i16>(&device, &config, sample_rate, channels, tx, dropped_chunks.clone(), err_tx.clone(), name.to_string()),
-        SampleFormat::U16 => build_input_stream::<u16>(&device, &config, sample_rate, channels, tx, dropped_chunks.clone(), err_tx.clone(), name.to_string()),
+        SampleFormat::F32 => build_input_stream::<f32>(
+            &device,
+            &config,
+            sample_rate,
+            channels,
+            tx,
+            dropped_chunks.clone(),
+            err_tx.clone(),
+            name.to_string(),
+        ),
+        SampleFormat::I16 => build_input_stream::<i16>(
+            &device,
+            &config,
+            sample_rate,
+            channels,
+            tx,
+            dropped_chunks.clone(),
+            err_tx.clone(),
+            name.to_string(),
+        ),
+        SampleFormat::U16 => build_input_stream::<u16>(
+            &device,
+            &config,
+            sample_rate,
+            channels,
+            tx,
+            dropped_chunks.clone(),
+            err_tx.clone(),
+            name.to_string(),
+        ),
         other => {
             return Err(KonError::AudioCaptureFailed(format!(
                 "unsupported sample format {other:?}"
@@ -386,8 +424,8 @@ fn open_and_validate(
         .map_err(|e| KonError::AudioCaptureFailed(format!("stream.play: {e}")))?;
 
     // Validation window: collect chunks for DEVICE_VALIDATION_MS, compute RMS.
-    let deadline = std::time::Instant::now()
-        + std::time::Duration::from_millis(DEVICE_VALIDATION_MS);
+    let deadline =
+        std::time::Instant::now() + std::time::Duration::from_millis(DEVICE_VALIDATION_MS);
     let mut collected: Vec<AudioChunk> = Vec::new();
     let mut total_samples = 0_usize;
     let mut sum_sq: f64 = 0.0;
@@ -513,11 +551,15 @@ mod tests {
 
     #[test]
     fn monitor_pattern_detection() {
-        assert!(is_monitor_name("alsa_output.pci-0000_00_1f.3.analog-stereo.monitor"));
+        assert!(is_monitor_name(
+            "alsa_output.pci-0000_00_1f.3.analog-stereo.monitor"
+        ));
         assert!(is_monitor_name("Monitor of Built-in Audio Analog Stereo"));
         assert!(is_monitor_name("Some Loopback Device"));
         assert!(!is_monitor_name("Blue Yeti USB"));
-        assert!(!is_monitor_name("alsa_input.pci-0000_00_1f.3.analog-stereo"));
+        assert!(!is_monitor_name(
+            "alsa_input.pci-0000_00_1f.3.analog-stereo"
+        ));
         assert!(!is_monitor_name(""));
     }
 }