Add classroom feedback integration design doc

Documents all user feedback issues and planned fixes for audio speed,
METAR normalization, phonetics, and UI text.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/plans/2025-02-14-classroom-feedback-design.md

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+# Classroom Feedback Integration — Design
+
+**Date:** 2025-02-14
+**Status:** Approved
+
+## Background
+
+User feedback from beta testers identified several friction points in the classroom experience. This design addresses all reported issues in a single pass.
+
+## Changes
+
+### 1. Audio Speed & Pausen
+
+**Problem:** Multiple users report ATC audio is too fast and hard to understand, especially SID/STAR names and METAR content.
+
+**Solution:**
+- Expand speed slider range from `0.7–1.3×` to `0.5–1.3×`
+- Lower default speed from `1.0` to `0.85×`
+- Insert comma-based pauses in METAR phrases to trigger natural TTS pausing between elements
+
+**Files:** `app/pages/classroom.vue` (slider config, default value)
+
+### 2. "Soll:" → "Expected:"
+
+**Problem:** German word "Soll" appears in the readback feedback UI (line 1068).
+
+**Solution:** Replace `Soll:` with `Expected:` — single string change.
+
+**Files:** `app/pages/classroom.vue` (line 1068)
+
+### 3. Pushback Delay Field Acceptance
+
+**Problem:** In the "Pushback Delay Acknowledgement" lesson, the delay field expects the word form (e.g. "five") but users type the numeral (e.g. "5"). The readback template already appends " minutes" as static text, so the field just needs the number.
+
+**Solution:** Add `scenario.pushDelayMinutes.toString()` to the `alternatives` array for the `push-delay` field.
+
+**Files:** `shared/data/learnModules.ts` (pushback-delay lesson, ~line 760)
+
+### 4. METAR Normalization for TTS
+
+**Problem:** METAR strings are sent to TTS as raw text (e.g. "BKN025"), making them unintelligible when spoken.
+
+**Solution:** New function `normalizeMetarPhrase()` in `shared/utils/radioSpeech.ts` that converts METAR codes to spoken aviation English:
+
+| Raw | Spoken |
+|-----|--------|
+| `28015KT` | `wind too eight zero degrees, wun fife knots` |
+| `28015G25KT` | `wind too eight zero degrees, wun fife gusting too fife knots` |
+| `9999` (vis) | `visibility wun zero kilometers or more` |
+| `BKN025` | `broken, too fife hundred feet` |
+| `SCT040` | `scattered, four thousand feet` |
+| `FEW010` | `few, wun thousand feet` |
+| `OVC008` | `overcast, eight hundred feet` |
+| `RA` | `rain` |
+| `SN` | `snow` |
+| `15/08` | `temperature wun fife, dew point zero eight` |
+
+Commas between elements provide natural TTS pauses. Integration: detect METAR context in `say()` (via lesson type or pattern) and route through `normalizeMetarPhrase()`.
+
+### 5. Phonetic Expansion for Approach Suffixes
+
+**Problem:** Approach types like "ILS 08R Y" don't get the suffix letter phonetized — user hears "why" instead of "Yankee".
+
+**Solution:** Add regex in `normalizeRadioPhrase()`:
+```
+/\b(ILS|VOR|RNAV|LOC|RNP)\s+(\d{2}[LCR]?)\s+([A-Z])\b/gi
+```
+Converts suffix letter to ICAO phonetic (Y → Yankee, Z → Zulu) and runway to spoken form.
+
+**Files:** `shared/utils/radioSpeech.ts`
+
+### 6. SID/STAR Suffix with Spaces
+
+**Problem:** Current SID pattern `/\b([A-Z]{4,6})(\s?)(\d)([A-Z])\b/g` handles `SUGOL2S` but not `SUGOL 2S` or `SUGOL 2 S`.
+
+**Solution:** Relax the regex to allow optional whitespace:
+```
+/\b([A-Z]{4,6})\s*(\d)\s*([A-Z])\b/g
+```
+
+**Files:** `shared/utils/radioSpeech.ts`
+
+## Out of Scope
+
+- Lesson navigation/search UX improvements (existing search works, needs user research)
+- Audio reliability issues (infrastructure/browser-dependent)
+- Classroom repetitiveness (pedagogical design, not code)