Allow --prune to skip confirmation with -f

[babarot]

WHAT

Make gomi --prune=<duration> skip the two confirmation prompts (and the file listing table) when -f/--force is passed. The existing --prune=orphans path already honors -f; this aligns the duration-based path with the same behavior.

Also drop the (dummy) marker from the -f/--force flag description, since the flag now has real effect under --prune.

Related: #126

WHY

Requested in #126 for scripting use cases. The user wants to run prune non-interactively from init scripts, for example:

[[ "$(tty)" == /dev/tty1 ]] && gomi -V > /dev/null && gomi --prune=30d -f

Today the duration-based prune always asks twice, so it cannot be used unattended. Reusing the existing -f flag avoids adding a new option, keeps parity with the orphans path, and matches what rm -f does conceptually.

Implementation gates the existing prompt block in permanentlyDeleteByTimeRange on !c.option.Rm.Force. When -f is not set, behavior is unchanged: files are listed, summary is printed, and both confirmations are required. When -f is set, gomi proceeds straight to deletion.

Verified manually: with backdated trashinfo files, gomi --prune=30d -f deletes matches without prompting, while gomi --prune=30d still shows the table and prompts as before. go test ./internal/cli/... passes.

[github-actions]

Code Metrics Report

	main (8c75e88)	#129 (19774ef)	+/-
Coverage	71.2%	71.2%	0.0%
Code to Test Ratio	1:1.5	1:1.5	0.0
Test Execution Time	7s	7s	0s

Details

  |                     | main (8c75e88) | #129 (19774ef) | +/-  |
  |---------------------|----------------|----------------|------|
  | Coverage            |          71.2% |          71.2% | 0.0% |
  |   Files             |             24 |             24 |    0 |
  |   Lines             |           1101 |           1101 |    0 |
  |   Covered           |            784 |            784 |    0 |
  | Code to Test Ratio  |          1:1.5 |          1:1.5 |  0.0 |
  |   Code              |           2739 |           2739 |    0 |
  |   Test              |           4280 |           4280 |    0 |
  | Test Execution Time |             7s |             7s |   0s |

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Reported by octocov