feat: KSUDP parser fix, warnings system, shift point rewrite, code quality (v0.5.1)

Bug Fixes:
- Fixed KSUDP binary parser offsets from packed (323B) to natural C
  alignment (328B) — 3 bytes padding after char identifier, 2 bytes
  after 6 bools
- Fixed setup_terminal() leaving terminal in raw mode on early exit

New Features:
- Thread-safe warning buffer (warnings.rs) with TUI bar + stderr fallback
- Rewrote shift point analysis per AC forum methodology: per-gear
  acceleration curves, crossover detection, same-gear merging
- UseCase::guidance() — step-by-step recording instructions
- Recording metadata enrichment in analysis responses
- recording_id field on sessions

Code Quality:
- Extracted finalize_run() helper (session.rs)
- Extracted execute_and_store_analysis() helper (api.rs)
- Extracted lerp_search<T>() generic helper (analysis.rs)

Breaking API Changes:
- GET /api/use-cases: string[] -> [{id, name, guidance}[]]
- Shift point analysis: gear_ranges/shift_events -> gear_curves/crossover_points

Updated README.md with new API response examples and TUI warning bar.

README.md

@@ -119,6 +119,7 @@ The terminal UI shows one panel per active feed:
 │ ╚  PCARS  Port :5606 ╝                                   │
 ├──────────────────────────────────────────────────────────┤
 │ Recording: 550e8400-…     Ctrl+C Quit                    │
+│ ⚠ Handshake response timed out (5s) — 12s ago           │
 └──────────────────────────────────────────────────────────┘
 ```
 
@@ -239,18 +240,52 @@ All fields are optional.
 }
 ```
 
+### Use Cases Response
+
+```json
+[
+  { "id": "shift_points", "name": "ShiftPoints", "guidance": "1. Drive to a long straight..." },
+  { "id": "track_map", "name": "TrackMap", "guidance": "1. Drive a complete lap..." }
+]
+```
+
+Each object contains:
+- `id` — use case identifier (use in session creation)
+- `name` — human-readable name
+- `guidance` — step-by-step instructions for the use case
+
 ### Shift Point Analysis Response
 
 ```json
 {
-  "gear_ranges": [
-    { "gear": 2, "gear_display": "1", "min_rpm": 3200, "max_rpm": 8500, "avg_rpm": 6100, "sample_count": 1200 },
-    { "gear": 3, "gear_display": "2", "min_rpm": 5800, "max_rpm": 8400, "avg_rpm": 7200, "sample_count": 900 }
+  "gear_curves": [
+    {
+      "gear": 2,
+      "gear_display": "1",
+      "run_label": "Run 1, Run 2 (2 runs)",
+      "data_points": [
+        { "speed_kmh": 45.2, "rpm": 3200, "acceleration_g": 0.85 },
+        { "speed_kmh": 55.8, "rpm": 4100, "acceleration_g": 0.82 }
+      ],
+      "min_rpm": 3200,
+      "max_rpm": 8500,
+      "min_speed_kmh": 45.0,
+      "max_speed_kmh": 120.0,
+      "sample_count": 1200
+    }
   ],
-  "shift_events": [
-    { "from_gear": 2, "to_gear": 3, "rpm_before_shift": 8400, "rpm_after_shift": 6100, "rpm_drop": 2300, "speed_kmh": 95.0 }
+  "crossover_points": [
+    {
+      "from_gear": 2,
+      "to_gear": 3,
+      "from_gear_display": "1",
+      "to_gear_display": "2",
+      "crossover_speed_kmh": 95.0,
+      "crossover_rpm": 7500
+    }
   ],
-  "recommended_shift_rpm": 8400.0,
+  "recommended_shift_rpm": 7500.0,
+  "runs_analyzed": 3,
   "total_frames_analyzed": 2100
 }
 ```
@@ -295,7 +330,8 @@ src/
 ├── parser_ksudp.rs         AC KSUDP binary parser (RTCarInfo, 6 tests)
 ├── parser_telemetry_tool.rs AC Telemetry Tool binary parser (357-byte driver struct, 7 tests)
 ├── parser_pcars.rs          PCARS 1 & 2 binary parser with auto-detection (5 tests)
-└── ui.rs                    Ratatui TUI rendering
+├── ui.rs                    Ratatui TUI rendering
+└── warnings.rs             Thread-safe warning buffer with TUI bar + stderr fallback
 ```
 
 ## License