Reorganize docs into v1 (beetfs) and v2 (new architecture)

docs/v1/ - Original beetfs documentation:
  - analysis.md, components.md, data-flow.md, drawbacks.md
  - features.md, modernization.md, rust-migration.md
  - benchmark-plan.md, benchmark-results.md, e2e-test-plan.md
  - README.md

docs/v2/ - New MusicFS architecture:
  - requirements.md: Full requirements spec (FR-1 to FR-25, NFR-1 to NFR-14)
    - P0: Multi-origin, plugins, CAS, control API
    - P1: Search, album art, prefetch, metadata sources
    - P3: HA, 10M+ files scalability
  - architecture.md: Google BlueDoc style design document
    - PlantUML diagrams for all components
    - Design requirements with quantitative targets
    - Alternatives considered, implementation plan

docs/v1/benchmark-results.md

@@ -0,0 +1,101 @@
+# beetfs Benchmark Results
+
+**Date**: 2026-05-12  
+**Status**: ❌ ALL BENCHMARKS BLOCKED BY BUGS
+
+## Executive Summary
+
+Benchmarks cannot complete due to critical bugs in beetfs. The implementation is non-functional for any library with content.
+
+## Results
+
+| Benchmark | Status | Mean | Error |
+|-----------|--------|------|-------|
+| mount_time | ❌ FAIL | N/A | Directory tree building bug |
+| readdir | ❌ FAIL | N/A | Directory tree building bug |
+| stat_latency | ❌ FAIL | N/A | Directory tree building bug |
+| enoent_lookup | ❌ FAIL | N/A | Directory tree building bug |
+| file_open | ❌ FAIL | N/A | Directory tree building bug |
+| read_throughput | ❌ FAIL | N/A | Directory tree building bug |
+| memory_usage | ❌ FAIL | N/A | Directory tree building bug |
+
+## Blocking Bugs
+
+### Bug #1: Nested Methods (Lines 758-1144)
+
+All FUSE operations (`readdir`, `open`, `read`, `write`, etc.) are indented inside the `access()` method, making them local functions instead of class methods.
+
+**Impact**: Even if mount succeeds, all file operations return `ENOSYS (Function not implemented)`.
+
+**Fix Required**: Dedent lines 758-1144 by 8 spaces.
+
+### Bug #2: Directory Tree Building (Lines 403-414)
+
+`FSNode.adddir()` calls `getnode()` which assumes parent directories already exist. When building the tree for a new library, parent directories haven't been created yet.
+
+**Error**:
+```
+KeyError: u'Bench Artist'
+  File "beetFs.py", line 403, in getnode
+    return self.getnode(elements, root=root.dirs[topdir])
+```
+
+**Impact**: Mount crashes when library contains any tracks.
+
+**Fix Required**: `adddir()` must create parent directories recursively before adding child.
+
+### Bug #3: Empty Library Only
+
+The only working configuration is mounting with an empty beets library:
+- `test_mount_empty_library`: ✅ PASS
+- Any library with tracks: ❌ CRASH
+
+## Test Environment
+
+- **Python**: 2.7.15
+- **OS**: Linux (NixOS)
+- **Test data**: 10 synthetic FLAC files (5 MB each)
+- **Beets**: 1.4.9
+
+## Benchmark Configuration
+
+```python
+num_tracks = 10
+track_size_mb = 5
+mount_runs = 3
+stat_runs = 20
+readdir_runs = 10
+```
+
+## Raw Results
+
+See `benchmarks/results/benchmark_results.json` for full JSON output.
+
+## Next Steps
+
+1. **Fix Bug #2** (directory tree building) - allows mount with content
+2. **Fix Bug #1** (nested methods) - allows FUSE operations to work
+3. **Re-run benchmarks** - get actual performance numbers
+
+## Conclusion
+
+**beetfs is currently non-functional** for real-world use. Both bugs must be fixed before performance can be measured. The test infrastructure and benchmark suite are ready; only the implementation needs repair.
+
+---
+
+## Appendix: E2E Test Results (For Reference)
+
+From the e2e test suite (74 tests):
+
+| Category | Passed | Failed | Errors |
+|----------|--------|--------|--------|
+| Smoke tests | 4 | 3 | 0 |
+| Nested bug detection | 3 (confirmed bug) | 10 | 0 |
+| Readdir | 0 | 10 | 0 |
+| Stat | 0 | 8 | 0 |
+| Read | 0 | 11 | 0 |
+| Write | 0 | 7 | 0 |
+| Error handling | 0 | 7 | 3 |
+| **Total** | **12** | **56** | **3** |
+
+The 12 passing tests are infrastructure tests and tests that verify the bugs exist.