refactor: improve report task tracking

[Flyrell]

Summary

• Command restructuring: Move log, edit, remove under log group command; move schedule commands under project/defaults groups; remove duplicate resolveProjectFromRepo in favor of ResolveProjectContext
• Time tracking improvements: Centralize day budget computation, replace proportional scaling with targeted segment carving for log deduction, add from/to time range support in edit/log/report overlays, use "(no task)" label for task-less log entries
• New features: Allow all three --from/--to/--duration flags in edit when consistent, add from/to time range display to report detail panel
• Documentation: Update all docs, README, and web pages to reflect restructured commands

Test plan

• Run task test to verify all unit tests pass
• Run task lint to verify no lint issues
• Manually test hourgit log add, hourgit log edit, hourgit log remove subcommands
• Verify hourgit project schedule get/set/reset/report commands work
• Verify hourgit defaults schedule get/set/reset/report commands work
• Check report table displays "(no task)" for untagged log entries

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