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/resample.rs

@@ -1,4 +1,6 @@
-use rubato::{SincFixedIn, SincInterpolationParameters, SincInterpolationType, Resampler, WindowFunction};
+use rubato::{
+    Resampler, SincFixedIn, SincInterpolationParameters, SincInterpolationType, WindowFunction,
+};
 
 use kon_core::constants::WHISPER_SAMPLE_RATE;
 use kon_core::error::{KonError, Result};
@@ -32,15 +34,9 @@ pub fn resample_to_16khz(audio: &AudioSamples) -> Result<AudioSamples> {
     };
 
     let mut resampler = SincFixedIn::<f32>::new(
-        ratio,
-        1.1,
-        params,
-        chunk_size,
-        1, // mono
+        ratio, 1.1, params, chunk_size, 1, // mono
     )
-    .map_err(|e| {
-        KonError::AudioDecodeFailed(format!("Resampler init failed: {e}"))
-    })?;
+    .map_err(|e| KonError::AudioDecodeFailed(format!("Resampler init failed: {e}")))?;
 
     let samples = audio.samples();
     let mut output_samples: Vec<f32> = Vec::new();
@@ -55,9 +51,9 @@ pub fn resample_to_16khz(audio: &AudioSamples) -> Result<AudioSamples> {
         }
 
         let input = vec![chunk];
-        let result = resampler.process(&input, None).map_err(|e| {
-            KonError::AudioDecodeFailed(format!("Resample failed: {e}"))
-        })?;
+        let result = resampler
+            .process(&input, None)
+            .map_err(|e| KonError::AudioDecodeFailed(format!("Resample failed: {e}")))?;
 
         if !result.is_empty() && !result[0].is_empty() {
             output_samples.extend_from_slice(&result[0]);
@@ -90,8 +86,7 @@ mod tests {
         let rate = 48000;
         let duration_secs = 1.0;
         let num_samples = (rate as f64 * duration_secs) as usize;
-        let samples: Vec<f32> =
-            (0..num_samples).map(|i| (i as f32 * 0.001).sin()).collect();
+        let samples: Vec<f32> = (0..num_samples).map(|i| (i as f32 * 0.001).sin()).collect();
 
         let input = AudioSamples::new(samples, rate, 1);
         let output = resample_to_16khz(&input).unwrap();