ComeOnOver Desktop Launcher v1.10.20

v1.10.20: Linux MVP M3 - real procfs Claude process scanner

Replaces the v1.10.19 EmptyClaudeProcessScanner stub with a real
ProcfsClaudeProcessScanner that walks /proc and matches Electron
"main" processes (cmdline contains app.asar AND no --type= flag).
Reuses the existing ClaudeProcessTreeAnalyser (pure function) for
descendant PID aggregation, so slot RAM/CPU totals work the same
as on Windows.

Verified against a real running Claude on Lewis's Ubuntu laptop:
13 electron processes total, 1 main identified, 12 helpers
correctly filtered.

Changes:
- New: ProcfsParser.cs (107 lines, pure functions) + 17 tests
- New: ProcfsClaudeProcessScanner.cs (157 lines)
- Deleted: EmptyClaudeProcessScanner.cs (superseded)
- RegexClaudeProcessClassifier regex: \ClaudeSlotN -> [\/]ClaudeSlotN
  so the same pattern matches Windows and Linux slot paths
- 2 new classifier tests cover Linux forward-slash paths
- DI swap in App.axaml.cs: ProcfsClaudeProcessScanner on Linux
- ROADMAP: v1.10.20 entry added; v1.10.5-v1.10.10 archived to
  docs/release-history/v1.10.md (keep ROADMAP under 200 lines)
- LEARNINGS: /proc/PID/stat parsing gotcha note

335/335 tests pass on Linux. 0 warnings, 0 errors. No Windows
regression (csproj/source paths unchanged for Windows compile).